Novel, phenolic compound, novel resol resin, cured products thereof, electrophotographic photosensitive member containing them, and process cartridge and electrophotographic apparatus which have the electrophotographic photosensitive member

ABSTRACT

A phenolic compound having a plurality of substituted hydroxyphenyl groups and charge-transportable structure, the substituted hydroxyphenyl groups of which have a hydroxymethyl group; and a resol resin obtained by allowing a phenolic compound having hydroxyphenyl groups and charge-transportable structure, to react with formaldehyde in the presence of a basic catalyst, and having charge-transportable structure. Also disclosed are a cured product and an electrophotographic photosensitive member which make use of the above, and a process cartridge and an electrophotographic apparatus which have the electrophotographic photosensitive member.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a novel phenolic compound, a novelresol resin, cured products thereof, an electrophotographicphotosensitive member containing them, and a process cartridge and anelectrophotographic apparatus which have the electrophotographicphotosensitive member.

[0003] 2. Related Background Art

[0004] Compounds having a hydroxyphenyl group, what are called phenoliccompounds, in particular, phenolic compounds having a hydroxymethylgroup in the hydroxyphenyl group (hydroxymethyl-group-containingphenolic compounds) are known to be used in various purposes. Forexample, they are applied to coating materials as disclosed in D. H.Solomon, “The Chemistry of Organic Film Formers”, and besides they areused in many fields such as lithographic printing plates, photoresists,adhesives, molding materials, laminating materials and binding agents.In these uses, specifically often used are phenol-formalin-resol resinsand compounds such as bishydroxymethyl-p-cresol andtetrakishydroxymethylbisphenol-A.

[0005] However, such known hydroxymethyl-group-containing phenoliccompounds and phenol-formalin-resol resins have by no means been thosehaving any charge-transportable structure in the molecule. Also, theyboth have so few hydroxymethyl groups in the molecule that anysufficient hard-film performance has not been achievable when used incoating materials, photosensitive printing plates or the like. In orderto make them satisfy such hard-film performance, it has been necessaryto add the hydroxymethyl-group-containing phenolic compound or resolresin in a large quantity.

[0006] Any compound does not yet exist which has in the same moleculethe charge-transportable structure and thehydroxymethyl-group-containing hydroxyphenyl group and also can form athree-dimensionally cross-linked structure alone upon heating to providea strong cured product.

[0007] In recent years, research and development are energetically madeon organic electrophotographic photosensitive members making use oforganic photoconductive materials in view of advantages that they have ahigh safety, have a superior productivity and are inexpensive. Inventionhas hitherto been made thereon in a great deal, and has been put intopractical use. However, electrophotographic photosensitive memberscomposed chiefly of a photoconductive polymer typified by poly-N-vinylcarbazole and a charge transfer complex formed of2,4,7-trinitrofluorenone or the like have not necessarily beensatisfactory in view of sensitivity, durability, residual potential andso forth.

[0008] Function-separated electrophotographic photosensitive members inwhich the function of charge generation and the function of chargetransport are allotted to respectively different materials have alsobrought about remarkable improvement in sensitivity and durability whichhave been considered disadvantageous in conventional organicelectrophotographic photosensitive members.

[0009] The function-separated electrophotographic photosensitive membershave also advantages that charge-generating materials andcharge-transporting materials are both available in wide ranges ofmaterial selection and that electrophotographic photosensitive memberswith desired characteristics can be produced relatively with ease.

[0010] As the charge-generating materials, various azo pigments,polycyclic quinone pigments, phthalocyanine pigments, cyanine dyes,squalic acid dyes, pyrylium salt dyes and so forth are known in the art.Also, as the charge-transporting materials, pyrazoline compounds,hydrazone compounds, triphenylamine compounds and so froth are known inthe art.

[0011] Now, with achievement of high image quality and high-speed andhigh-durability image formation in recent years, the organicelectrophotographic photosensitive members are also required to be moreimproved in mechanical durability.

[0012] In recent years, electrophotographic apparatus such as printers,copying machines and facsimile machines making use ofelectrophotographic photosensitive members have also come into wide usein various fields, and are more severely required to provide imageswhich are always stable even in more various environments, and theelectrophotographic photosensitive members have come to have a highpossibility of being exposed to chemical, electrical and mechanicalimpact against its surface characteristics. Accordingly, requirementsfor surface layers have come severer.

[0013] Electrophotographic photosensitive members, to which electricaland mechanical external forces are directly applied, are required tohave durabilities to such forces. Stated specifically, they are requiredto have durability to the occurrence of surface wear and scratches dueto friction and durability to the deterioration of surface layer that iscaused by adhesion of active substances such as ozone and nitrogenoxides generated at the time of charging.

[0014] In addition, electrophotographic photosensitive members arerepeatedly put to the steps of charging, exposure, development,transfer, cleaning and charge elimination. Electrostatic latent imagesformed upon charging and exposure are made into toner images by the useof a particulate developer called a “toner”. The toner images arefurther transferred to a transfer material such as paper by a transfermeans, where it is not that the toner of the toner images is alltransferred but that it remains partly on the surface of thephotosensitive member as a residual toner.

[0015] If this residual toner is in a large quantity, the images on thetransfer material come into images with what is called “crumbling blankareas”. This not only results in lack of image uniformity but also maycause a problem that the melt adhesion of toner or filming occurs on theelectrophotographic photosensitive member. To solve such a problem, itis required to improve the releasability of the surface layer of theelectrophotographic photosensitive member.

[0016] To meet such requirements, it has been attempted to provideprotective layers of various types. Among various attempts, protectivelayers composed chiefly of resins have been proposed in a large number.For example, in Japanese Patent Application Laid-open No. 57-30846, aprotective layer is disclosed which is formed of a resin to which ametal oxide is added as conductive particles so that its volumeresistivity can be controlled. Japanese Patent Application Laid-open No.5-181299 also discloses use of a curable phenolic resin as a resin forprotective layers. Japanese Patent Application Laid-open No. 5-181299and so forth further discloses an example in which a phenolic resin isused as a binder resin for surface layers.

[0017] Under existing circumstances, however, even these protective orsurface layers have not achieved any durability, releasability and soforth against various impact to surface and against wear and scratching,which are properties well satisfactory as protective layers.

[0018] The achievement of an electrophotographic photosensitive memberhaving high durability and less abrasion level may also result in alowering of surface resistance of the electrophotographic photosensitivemember, caused by adhesion of charge products or paper dust. This isremarkable especially in an environment of high temperature and highhumidity. These have brought about an additional problem that streakyblurred images, what is called “smeared images”, may occur in therotational direction of the electrophotographic photosensitive member.

[0019] Highly durable electrophotographic photosensitive members havingexcellent stability to environmental variations do not yet have anysufficient performance.

SUMMARY OF THE INVENTION

[0020] An object of the present invention is to provide a novel phenoliccompound and a novel resol resin, in particular, a novel phenoliccompound and a novel resol resin which are able to endowelectrophotographic photosensitive members with excellent properties(surface properties) to improve durability to the occurrence of wear andscratches, lessen residual-potential increase and potential variations,and maintain high-grade image quality over a long period of time, andalso provide cured products thereof.

[0021] Another object of the present invention is to provide anelectrophotographic photosensitive member having a surface layercontaining the above novel phenolic compound or novel resol resin, i.e.,an electrophotographic photosensitive member which has a high durabilityto the occurrence of wear and scratches, has small residual-potentialincrease and potential variations, can maintain high-grade image qualityover a long period of time and, even in electrophotographicphotosensitive members having been made highly durable, does not causeany smeared images when used over a long period of time in anenvironment of high temperature and high humidity; and a processcartridge and an electrophotographic apparatus which have such anelectrophotographic photosensitive member.

[0022] That is, the present invention is a phenolic compound comprisinga compound having a plurality of substituted hydroxyphenyl groups andcharge-transportable structure;

[0023] at least one of the substituted hydroxyphenyl groups having atleast one hydroxymethyl group as a substituent.

[0024] The present invention is also a resol resin comprising a resinobtained by allowing a phenolic compound having hydroxyphenyl groups andcharge-transportable structure, to react with formaldehyde in thepresence of a basic catalyst;

[0025] the resin having charge-transportable structure.

[0026] The present invention is still also a cured product of a phenoliccompound, comprising a cured product obtained by curing a phenoliccompound having a hydroxymethyl group, wherein;

[0027] the phenolic compound is a phenolic compound having a pluralityof substituted hydroxyphenyl groups and charge-transportable structure;

[0028] at least one of the substituted hydroxyphenyl groups having atleast one hydroxymethyl group as a substituent.

[0029] The present invention is further a cured product of a resolresin, comprising a cured product obtained by curing a resol resin,wherein;

[0030] the resol resin is a resol resin obtained by allowing a phenoliccompound having hydroxyphenyl groups and charge-transportable structure,to react with formaldehyde in the presence of a basic catalyst;

[0031] the resol resin having charge-transportable structure.

[0032] The present invention is still further an electrophotographicphotosensitive member comprising a support and provided thereon aphotosensitive layer, wherein;

[0033] the electrophotographic photosensitive member has a surface layerwhich contains a cured product of a phenolic compound having a pluralityof substituted hydroxyphenyl groups and charge-transportable structure;

[0034] at least one of the substituted hydroxyphenyl groups having atleast one hydroxymethyl group as a substituent.

[0035] The present invention is still further an electrophotographicphotosensitive member comprising a support and provided thereon aphotosensitive layer, wherein;

[0036] the electrophotographic photosensitive member has a surface layerwhich contains a cured product of a resol resin obtained by allowing aphenolic compound having hydroxyphenyl groups and charge-transportablestructure, to react with formaldehyde in the presence of a basiccatalyst;

[0037] the resol resin having charge-transportable structure.

[0038] The present invention is still further a process cartridgecomprising an electrophotographic photosensitive member and at least onemeans selected from the group consisting of a charging means, adeveloping means, a transfer means and a cleaning means which areintegrally supported, and being detachably mountable to the main body ofan electrophotographic apparatus, wherein;

[0039] the electrophotographic photosensitive member is anelectrophotographic photosensitive member comprising a support andprovided thereon a photosensitive layer;

[0040] the electrophotographic photosensitive member having a surfacelayer which contains a cured product of a phenolic compound having aplurality of substituted hydroxyphenyl groups and charge-transportablestructure;

[0041] at least one of the substituted hydroxyphenyl groups having atleast one hydroxymethyl group as a substituent.

[0042] The present invention is still further a process cartridgecomprising an electrophotographic photosensitive member and at least onemeans selected from the group consisting of a charging means, adeveloping means, a transfer means and a cleaning means which areintegrally supported, and being detachably mountable to the main body ofan electrophotographic apparatus, wherein;

[0043] the electrophotographic photosensitive member is anelectrophotographic photosensitive member comprising a support andprovided thereon a photosensitive layer;

[0044] the electrophotographic photosensitive member having a surfacelayer which contains a cured product of a resol resin obtained byallowing a phenolic compound having hydroxyphenyl groups andcharge-transportable structure, to react with formaldehyde in thepresence of a basic catalyst;

[0045] the resol resin having charge-transportable structure.

[0046] The present invention is still further an electrophotographicapparatus comprising an electrophotographic photosensitive member, acharging means, an exposure means, a developing means and a transfermeans, wherein;

[0047] the electrophotographic photosensitive member is anelectrophotographic photosensitive member comprising a support andprovided thereon a photosensitive layer;

[0048] the electrophotographic photosensitive member having a surfacelayer which contains a cured product of a phenolic compound having aplurality of substituted hydroxyphenyl groups and charge-transportablestructure;

[0049] at least one of the substituted hydroxyphenyl groups having atleast one hydroxymethyl group as a substituent.

[0050] The present invention is still further an electrophotographicapparatus comprising an electrophotographic photosensitive member, acharging means, an exposure means, a developing means and a transfermeans, wherein;

[0051] the electrophotographic photosensitive member is anelectrophotographic photosensitive member comprising a support andprovided thereon a photosensitive layer;

[0052] the electrophotographic photosensitive member having a surfacelayer which contains a cured product of a resol resin obtained byallowing a phenolic compound having hydroxyphenyl groups andcharge-transportable structure, to react with formaldehyde in thepresence of a basic catalyst;

[0053] the resol resin having charge-transportable structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0054]FIGS. 1A, 1B and 1C each illustrate the layer construction of theelectrophotographic photosensitive member of the present invention.

[0055]FIG. 2 is a schematic illustration of the construction of anelectrophotographic apparatus provided with a process cartridge havingthe electrophotographic photosensitive member of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] The present invention is described below in greater detail.

[0057] The novel phenolic compound of the present invention is aphenolic compound having charge-transportable structure, which ischaracterized by having a plurality of substituted hydroxyphenyl groupsand charge-transportable structure.

[0058] The phenolic compound having hydroxyphenyl groups andcharge-transportable structure is meant to be a compound having in thesame molecule, together with a plurality of hydroxyphenyl groups, astructure having the function to transport electric charges(charge-transportable structure) such as a triarylamine structure, astilbene structure, a hydrazone structure, a pyrazoline structure and atriphenylmethane structure. Among these charge-transportable structures,a triarylamine structure is preferred.

[0059] The novel phenolic compound of the present invention is, amongphenolic compounds having hydroxyphenyl groups and charge-transportablestructure, a phenolic compound in which at least one of thehydroxyphenyl groups the compound has is a hydroxyphenyl group having ahydroxymethyl group as a substituent (i.e., ahydroxymethyl-group-containing phenolic compound).

[0060] Incidentally, in the present invention, hydroxyphenyl groupshaving a substituent is expressed as substituted hydroxyphenyl groups.Among the substituted hydroxyphenyl groups, groups having ahydroxymethyl group as the substituent are expressed ashydroxymethyl-group-containing hydroxyphenyl groups.

[0061] Among the hydroxyphenyl groups (inclusive of substitutedhydroxyphenyl groups), what is called p-hydroxyphenyl groups arepreferred whose phenyl groups and other moiety skeleton are linked atthe position which is the p-position as viewed from the hydroxy groups.

[0062] Among the hydroxymethyl-group-containing hydroxyphenyl groups,hydroxymethyl-group-containing hydroxyphenyl groups are preferred atleast one of the hydroxymethyl groups of which is linked at the positionwhich is the o-position in respect to any of the hydroxyl groups in thehydroxymethyl-group-containing hydroxyphenyl groups.

[0063] Stated further, among the above novel phenolic compounds of thepresent invention, more preferred is a hydroxymethyl-group-containingphenolic compound having structure represented by any one of thefollowing Formulas (1) to (5).

[0064] In Formula (1), R¹¹ represents a divalent hydrocarbon grouphaving 1 to 8 carbon atoms and which may be branched. R¹² represents ahydrogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted aralkyl group or a substituted or unsubstituted phenylgroup. Ar¹¹ and Ar¹² each independently represent a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup. Ar¹³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group. Letter symbols m and n are eachindependently 0 or 1. X¹¹ to X¹⁴ each independently represent a hydrogenatom or a hydroxymethyl group, provided that at least one of X¹¹ to X¹⁴is a hydroxymethyl group.

[0065] In Formula (2), R²¹ represents a divalent hydrocarbon grouphaving 1 to 8 carbon atoms and which may be branched. Ar²¹ and Ar²² eachindependently represent a substituted or unsubstituted alkyl group, asubstituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group. Thetwo benzene rings may combine to form a ring via R²¹. A letter symbol pis 0 or 1. X²¹ and X²² each independently represent a hydrogen atom or ahydroxymethyl group, provided that at least one of X²¹ and X²² is ahydroxymethyl group.

[0066] In Formula (3), R³¹ and R³² each independently represent adivalent hydrocarbon group having 1 to 8 carbon atoms and which may bebranched. Ar³¹ represents a substituted or unsubstituted alkyl group, asubstituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group. Thetwo benzene rings linked via R³¹ may combine to form a ring via R³¹. Thetwo benzene rings linked via R³² may combine to form a ring via R³².Letter symbols q and r are each independently 0 or 1. X³¹ to X³⁴ eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X³¹ to X³⁴ is a hydroxymethyl group.

[0067] In Formula (4), R⁴¹ to R⁴³ each independently represent adivalent hydrocarbon group having 1 to 8 carbon atoms and which may bebranched. The two benzene rings linked via R⁴¹ may combine to form aring via R⁴¹. The two benzene rings linked via R⁴² may combine to form aring via R⁴². The two benzene rings linked via R⁴³ may combine to form aring via R⁴³. Letter symbols s, t and u are each independently 0 or 1.X⁴¹ to X⁴⁶ each independently represent a hydrogen atom or ahydroxymethyl group, provided that at least one of X⁴¹ to X⁴⁶ is ahydroxymethyl group.

[0068] In Formula (5), R⁵² represents a divalent hydrocarbon grouphaving 1 to 8 carbon atoms and which may be branched. Z⁵¹ and Z⁵² eachindependently represent a hydrogen atom, a halogen atom, a substitutedor unsubstituted alkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted monovalent aromatic hydrocarbonring group or a substituted or unsubstituted monovalent aromaticheterocyclic group. The benzene ring having Z⁵¹ and the benzene ringhaving Z⁵² may combine via Z⁵¹ or Z⁵² to form a ring. A letter symbol vis 0 or 1. A letter symbol w is an integer of 1 to 4. X⁵¹ and X⁵² eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁵¹ and X⁵² is a hydroxymethyl group.

[0069] The novel resol resin of the present invention is, as describedpreviously, a resol resin obtained by allowing a phenolic compoundhaving hydroxyphenyl groups and charge-transportable structure, to reactwith formaldehyde in the presence of a basic catalyst, and is a resolresin having charge-transportable structure.

[0070] The charge-transportable structure may include, like the abovehydroxymethyl-group-containing phenolic compound of the presentinvention, a triarylamine structure, a stilbene structure, a hydrazonestructure, a pyrazoline structure and a triphenylmethane structure.Among these, a triarylamine structure is preferred.

[0071] The hydroxyphenyl groups of the phenolic compound serving as araw material of the resol resin has may also preferably be ap-hydroxyphenyl group.

[0072] Among phenolic compounds having hydroxyphenyl groups andcharge-transportable structure, serving as raw materials of the resolresin of the present invention, more preferred is a phenolic compoundhaving structure represented by any one of the following Formulas (6) to(10) is preferred.

[0073] In Formula (6), R⁶¹ represents a divalent hydrocarbon grouphaving 1 to 8 carbon atoms and which may be branched. R⁶² represents ahydrogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted aralkyl group or a substituted or unsubstituted phenylgroup. Ar⁶¹ and Ar⁶² each independently represent a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup. Ar⁶³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group. Letter symbols m′ and n′ are eachindependently 0 or 1.

[0074] In Formula (7), R⁷¹ represents a divalent hydrocarbon grouphaving 1 to 8 carbon atoms and which may be branched. Ar⁷¹ and Ar⁷² eachindependently represent a substituted or unsubstituted alkyl group, asubstituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group. Thetwo benzene rings may combine to form a ring via R⁷¹. A letter symbol p′is 0 or 1.

[0075] In Formula (8), R⁸¹ and R⁸² each independently represent adivalent hydrocarbon group having 1 to 8 carbon atoms and which may bebranched. Ar⁸¹ represents a substituted or unsubstituted alkyl group, asubstituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group. Thetwo benzene rings linked via R⁸¹ may combine to form a ring via R⁸¹. Thetwo benzene rings linked via R⁸² may combine to form a ring via R⁸².Letter symbols q′ and r′ are each independently 0 or 1.

[0076] In Formula (9), R⁹¹ to R⁹³ each independently represent adivalent hydrocarbon group having 1 to 8 carbon atoms and which may bebranched. The two benzene rings linked via R⁹¹ may combine to form aring via R⁹¹. The two benzene rings linked via R⁹² may combine to form aring via R⁹². The two benzene rings linked via R⁹³ may combine to form aring via R⁹³. Letter symbols s′, t′ and u′ are each independently 0 or1.

[0077] In Formula (10), R¹⁰² represents a divalent hydrocarbon grouphaving 1 to 8 carbon atoms and which may be branched. Z¹⁰¹ and Z¹⁰² eachindependently represent a hydrogen atom, a halogen atom, a substitutedor unsubstituted alkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted monovalent aromatic hydrocarbonring group or a substituted or unsubstituted monovalent aromaticheterocyclic group. The benzene ring having Z¹⁰¹ and the benzene ringhaving Z¹⁰² may combine via Z¹⁰¹ or Z¹⁰² to form a ring. A letter symbolv′ is 0 or 1. A letter symbol w′ is an integer of 1 to 4.

[0078] Structures such as the substituents in the above Formulas (1) to(10) are described below.

[0079] The divalent hydrocarbon groups having 1 to 8 carbon atoms andwhich may be branched may include a methylene group, an ethylene group,a propylene group and a butylene group.

[0080] The alkyl group may include a methyl group, an ethyl group, apropyl group and a butyl group. The aralkyl group may include a benzylgroup, a phenethyl group and a naphthylmethyl group. The monovalentaromatic hydrocarbon ring group may include a phenyl group, a naphthylgroup, an anthryl group and a pyrenyl group. The monovalent aromaticheterocyclic group may include a pyridyl group, a thienyl group, a furylgroup and a quinolyl group.

[0081] The divalent aromatic hydrocarbon ring group may include aphenylene group, a naphthylene group, an anthrylene group and apyrenylene group. The divalent aromatic heterocyclic group may include apyridilene group and a thienylene group.

[0082] The halogen atom may include a fluorine atom, a chlorine atom, abromine atom and an iodine atom.

[0083] In the case in which the benzene ring having Z⁵¹ or Z¹⁰¹ and thebenzene ring having Z⁵² or Z¹⁰¹ combine via Z⁵¹ or Z⁵², or Z¹⁰¹ or Z¹⁰²,respectively, to form a ring, the ring may specifically include cyclicstructures such as a fluorene skeleton and a dihydrophenanthreneskeleton.

[0084] The substituents the above groups may have may include alkylgroups such as a methyl group, an ethyl group, a propyl group and abutyl group; aralkyl groups such as a benzyl group, a phenethyl groupand a naphthylmethyl group; monovalent aromatic hydrocarbon ring groupssuch as a phenyl group, a naphthyl group, an anthryl group, a pyrenylgroup, a fluorenyl group, a carbazolyl group, a dibenzofuryl group and adibenzothiophenyl; alkoxyl groups such as a methoxyl group, an ethoxylgroup and a propoxyl group; aryloxyl groups such as a phenoxyl group anda naphthoxyl group; halogen atoms such as a fluorine atom, a chlorineatom, a bromine atom and an iodine atom; and a nitro group and a cyanogroup.

[0085] The hydroxymethyl-group-containing phenolic compound of thepresent invention is obtained by allowing the phenolic compound havinghydroxyphenyl groups and charge-transportable structure to react withformaldehyde in the presence of a basic catalyst to introduce at leastone hydroxymethyl group into the hydroxyphenyl group of the phenoliccompound.

[0086] The phenolic compound having hydroxyphenyl groups andcharge-transportable structure and the formaldehyde may preferably befed in a molar ratio of from 1:2 to 1:30, and more preferably from 1:6to 1:18 from the viewpoint of yield.

[0087] The reaction may preferably be carried out at a temperature offrom 0° C. to 80° C., and more preferably from 10° C. to 60° C. At atemperature lower than 0° C., the reaction may proceed slowly. At atemperature higher than 80° C., gelation may occur. The reaction timemay vary depending on the reaction temperature. For example, in the caseof 40° C., the reaction may preferably be carried out for 4 hours to 10days, and more preferably for 12 hours to 5 days.

[0088] Usually, the reaction of the phenolic compound with theformaldehyde takes place predominantly at the o-position or p-positionas viewed from the hydroxyl groups of the hydroxyphenyl groups. Wherethe hydroxyphenyl groups are p-hydroxyphenyl groups, the addition ofhydroxymethyl groups derived from the formaldehyde often takes place onthe o-position. However, the addition may take place on the m-positionin side reaction or the like.

[0089] The resol resin of the present invention, havingcharge-transportable structure, may also be obtained by the same methodas the synthesis of the above hydroxymethyl-group-containing phenoliccompound of the present invention, having charge-transportablestructure.

[0090] In the present invention, the resol resin refers to a mixturewhich is in the state the degree of introduction of hydroxymethyl groupsand the intermolecular condensation product are appropriately set byarbitrarily controlling hydroxymethylation reaction to freely change themixing ratio of hydroxymethyl groups and the molecular weightdistribution. Hence, intentionally or unintentionally the resol resincontains not only monomers but also oligomers, and has broadercomposition than the phenolic compound.

[0091] The resol resin may contain not only a monomer structure but alsoan oligomer such as a dimer or a trimer as exemplified later.Hydroxymethyl groups formed in the middle of hydroxymethylation reactionfurther cause condensation or addition reaction such as dehydration orremoval of formaldehyde at hydroxymethyl groups each other or at othersites on the hydroxyphenyl groups to form linkages between molecules tocome into an oligomer.

[0092] The phenolic compound having hydroxyphenyl groups andcharge-transportable structure and the formaldehyde may be fed, as apreferably range, in the same molar ratio as the case of synthesizingthe above hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention.

[0093] The basic catalyst may preferably be used in an amount of from 5mol % to 300 mol % based on the phenolic compound having hydroxyphenylgroups and charge-transportable structure. This basic catalyst has alsothe action to dissolve in an aqueous reaction solvent the phenoliccompound having hydroxyphenyl groups and charge-transportable structure,and may appropriately be used in a quantity made large or smallaccording to the solvent to be used.

[0094] The reaction may preferably be carried out at a temperature offrom 0° C. to 80° C., and more preferably from 10° C. to 60° C. At atemperature lower than 0° C., the reaction may proceed slowly. At atemperature higher than 80° C., gelation may occur. The reaction timemay vary depending on the reaction temperature. For example, in the caseof 50° C., the reaction may preferably be carried out for 2 hours to 5days. In this case, any reaction carried out for too long time may causegelation.

[0095] The resol resin having charge-transportable structure of thepresent invention may also contain those in which thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention has come into anoligomer because of the condensation of hydroxymethyl groups and thelike.

[0096] As the formaldehyde used when the hydroxymethyl-group-containingphenolic compound having charge-transportable structure or resol resinhaving charge-transportable structure of the present invention, eitherof formalin and paraformaldehyde may be used.

[0097] As the basic catalyst used when thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure or resol resin havingcharge-transportable structure of the present invention, any knownorganic base or inorganic basic catalyst may be used.

[0098] As the organic basic catalyst, amine catalysts such as ammonia(water), tetramethylammonium hydroxide, tetraethylammonium hydroxide,triethylamine, diethylamine, monoethylamine, trimethylamine,dimethylamine, monomethylamine, morpholine and N-methylmorpholine arepreferred. In particular, tertiary alkylamines are more preferred.

[0099] As the inorganic basic catalyst, catalysts containing alkalimetals or alkaline earth metals, such as sodium hydroxide, potassiumhydroxide, lithium hydroxide and calcium hydroxide are preferred.

[0100] The cured product of the phenolic compound described above andcured product of the resol resin described above, of the presentinvention, is in the state that, like what is meant by commonlyavailable cured products, monomers or oligomers have caused reactionsuch as condensation or addition by means of functional groups to form athree-dimensionally polymeric network, and the product can be consideredto have cured where it turns insoluble in solvents in which it had beensoluble before it cures.

[0101] Where the hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure or resol resin havingcharge-transportable structure of the present invention is used in asurface layer of the electrophotographic photosensitive member, a curedcomposition obtained from the phenolic compound or resol resin may havea low resistance if the basic catalyst and any salt formed byneutralizing it remain in the cured composition. This may cause alowering of image quality of electrophotographic images especially in anenvironment of high temperature and high humidity. Accordingly, it ispreferable for the product to pass through the step of removing thebasic catalyst after the hydroxymethyl-group-containing phenoliccompound having charge-transportable structure or resol resin havingcharge-transportable structure of the present invention has beenobtained.

[0102] The basic catalyst may preferably be neutralized with an acidafter the reaction has been completed. As the acid to be used, either ofinorganic acids such as sulfuric acid, hydrochloric acid, nitric acidand phosphoric acid and organic acids such as benzenesulfonic acid,p-toluenesulfonic acid and acetic acid may be used. Salts producedthrough such a neutralization step may further preferably be removed by,e.g., repeating washing with water.

[0103] Where the basic catalyst is an amine catalyst, it can be removedunder reduced pressure after the reaction has been completed. In thatcase, tertiary amines are most readily removable.

[0104] Where the hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure is one having crystallizability, anycommon step of purification such as recrystallization andreprecipitation may be provided to remove the catalyst.

[0105] Next, specific examples of the phenolic compound havinghydroxyphenyl groups and charge-transportable structure, used to obtainthe hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure or resol resin havingcharge-transportable structure of the present invention are shown below.Note that the present invention is by no means limited to these specificexamples.

[0106] Next, specific examples of the hydroxymethyl-group-containingphenolic compound having charge-transportable structure of the presentinvention are shown below. Note that the present invention is by nomeans limited to these specific examples.

[0107] The above specific examples are examples in which hydroxymethylgroups have been substituted at all the o-positions of the hydroxylgroups. In the present invention, however, at least one of thehydroxyphenyl groups may be a substituted hydroxyphenyl group having thehydroxymethyl group as a substituent. A mixture of those havingdifferent number of substitution of hydroxymethyl groups is alsoembraced in the phenolic compound of the present invention.

[0108] Next, as estimated structure of the oligomer contained in theresol resin having charge-transportable structure of the presentinvention, examples of products synthesized using the above (P-22) as araw material are shown below. Note that the present invention is by nomeans limited to these examples.

[0109] The structure of the oligomer may have a variety of combinationin respect of the position of linkage, the form of linkage, the numberof monomers connected and so forth. The above estimated structures arenothing but very some examples. The resol resin of the present inventionis a mixture of such an oligomer and a monomer having hydroxymethylgroups.

[0110] In the phenolic compound and resol resin of the presentinvention, hydroxymethyl groups mutually cause dehydration condensationor formaldehyde removal reaction with ease upon heating to formadditional linkages.

[0111] The hydroxymethyl groups also cause dehydration condensationreaction with hydrogen atoms at the oppositions as viewed from thehydroxyl groups of (chiefly) hydroxyphenyl groups having not yet beensubstituted, to form methylene linkages.

[0112] These reactions can be represented by reaction schemes as amodel, which are as follows.

[0113] These reactions are reactions which take place specifically wherehydroxymethyl groups are substituted on hydroxyphenyl groups to comepresent there. In other substituents, such curing reaction does notproceed.

[0114] The curing reaction begins to proceed at a relatively lowtemperature of about 130° C. to 160° C. The phenolic compound and resolresin of the present invention may be diluted with a solvent to preparea coating material, and the coating material may preferably be coated onthe surface of an object, followed by removal of the solvent and drying,and also heating to the temperature at which the curing reactionproceeds, to effect drying and also heat curing.

[0115] As estimated structure of the cured product of the presentinvention, an example of a product obtained by curing the phenoliccompound or resol resin synthesized using the above (P-22) as a rawmaterial is shown below. Note that the present invention is by no meanslimited to this example.

[0116] (In the above Formula (S-22), M represents a methyl group.)

[0117] It is shown that the hydroxymethyl groups on the hydroxyphenylgroups of the phenolic compound has are rich in reactivity fordehydration, formaldehyde removal, addition and so forth upon heatingand hence readily form linkages between molecules to form athree-dimensional cured structure. Chiefly, the hydroxymethyl groupsbetween molecules react to form benzyl-ether linkages or methylenelinkages. Thus, the curing is accomplished.

[0118] The above (S-22) is the estimated structure to the last. As amatter of course, it may differ depending on the structure of sidereaction or the like and on production conditions.

[0119] Incidentally, the cured products obtained from the phenoliccompound and resol resin of the present invention have, in both cases,like structure as exemplified by the above (S-22).

[0120] As uses of the phenolic compound and resol resin of the presentinvention, besides electrophotographic photosensitive members describedlater, the phenolic compound and resol resin may also be used in deviceswhich require thin films having charge-transporting function. Forexample, they may be used as members or films requiringcharge-transporting function, of image sensors, electroluminescentdevices, optical memories, solar cells and electrophotographicengravers.

[0121] The electrophotographic photosensitive member of the presentinvention is described below. The following description of theelectrophotographic photosensitive member is description taking the caseof those making use of (the cured product) of the phenolic compound ofthe present invention. The case of those making use of (the curedproduct) of the resol resin is also entirely alike.

[0122] The electrophotographic photosensitive member of the presentinvention comprises a support and provided thereon a photosensitivelayer.

[0123] The photosensitive layer the electrophotographic photosensitivemember of the present invention has may have any known layerconstruction such as a single-layer type in which it has acharge-generating material and a charge-transporting material in thesame layer, a regular-layer type in which a charge generation layercontaining a charge-generating material and a charge transport layercontaining a charge-transporting material are superposed in this order,and a reverse-layer type in which a charge transport layer containing acharge-transporting material and a charge generation layer containing acharge-generating material are superposed in this order. Theregular-layer type photosensitive layer is preferred in view ofelectrophotographic performance.

[0124] Note here that the hydroxymethyl-group-containing phenoliccompound having charge-transportable structure of the present inventioncan have the effect of high durability when used in a surface layer ofthe electrophotographic photosensitive member. Accordingly, it maypreferably be used as a material for a protective layer provided on thephotosensitive layer having the above layer construction of asingle-layer type, regular-layer type or reverse-layer type, or used asa material simultaneously having both functions as a charge-transportingmaterial and a binder resin, for the single-layer type photosensitivelayer or for the regular-layer type photosensitive layer. In particular,it may more preferably be used as the material for a protective layer.

[0125]FIG. 1A shows an example of an electrophotographic photosensitivemember comprising a support 4 and provided thereon a charge generationlayer 3 and a charge transport layer 2 in this order, and a protectivelayer 1 further provided as the surface layer of the electrophotographicphotosensitive member.

[0126] As also shown in FIGS. 1B and 1C, an intermediate layer 5 andalso a conductive layer 6 aiming at prevention of interference fringesmay further be provided between the support 4 and the charge generationlayer 3.

[0127] In the case when the photosensitive layer is the single-layertype photosensitive layer, the layer may be provided by film-forming onelayer having a charge-generating material and a charge-transportingmaterial simultaneously.

[0128] As the, support of the electrophotographic photosensitive memberof the present invention, it may be one having conductivity. Usable aresupports having conductivity in themselves, as exemplified by those madeof aluminum, aluminum alloy or stainless steel, and besides, thesesupports or plastic supports having layers film-formed by vacuumdeposition of aluminum, aluminum alloy or indium oxide-tin oxide alloy,supports comprising plastic or paper impregnated with conductive fineparticles (e.g., carbon black, tin oxide, titanium oxide or silverparticles) together with a suitable binder resin, and also plasticshaving a conductive binder resin.

[0129] An intermediate layer (an adhesion layer) having the function asa barrier and the function of adhesion may be provided between thesupport and the photosensitive layer. The intermediate layer is formedfor the purposes of, e.g., improving the adhesion of the photosensitivelayer, improving coating performance, protecting the support, coveringany defects of the support, improving the injection of electric chargesfrom the support and protecting the photosensitive layer from anyelectrical breakdown. The intermediate layer may be formed of, e.g.,casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acidcopolymer, polyamide, modified polyamide, polyurethane, gelatin oraluminum oxide. The intermediate layer may preferably have a layerthickness of 5 μm or less, and more preferably from 0.1 μm to 3 μm.

[0130] The charge generation layer of the electrophotographicphotosensitive member of the present invention is formed of a binderresin with a charge-generating material dispersed therein.

[0131] The charge-generating material used in the electrophotographicphotosensitive member of the present invention may include:

[0132] (1) azo pigments such as monoazo, disazo and trisazo;

[0133] (2) phthalocyanine pigments such as metal phthalocyanines andmetal-free phthalocyanine;

[0134] (3) indigo pigments such as indigo and thioindigo;

[0135] (4) perylene pigments such as perylene acid anhydrides andperylene acid imides;

[0136] (5) polycyclic quinone pigments such as anthraquinone andpyrenequinone;

[0137] (6) squarilium dyes;

[0138] (7) pyrylium salts and thiapyrylium salts;

[0139] (8) triphenylmethane dyes;

[0140] (9) inorganic materials such as selenium, selenium-tellurium andamorphous silicon;

[0141] (10) quinacridone pigments;

[0142] (11) azulenium salt pigments;

[0143] (12) cyanine dyes;

[0144] (13) xanthene dyes;

[0145] (14) quinoneimine dyes;

[0146] (15) styryl dyes;

[0147] (16) cadmium sulfide; and

[0148] (17) zinc oxide.

[0149] Of these, azo pigments, phthalocyanine pigments, perylenepigments, polycyclic quinone pigments and azulenium salt pigments arepreferred. Azo pigments and phthalocyanine pigments are more preferred.

[0150] The binder resin used to form the charge generation layer mayinclude, e.g., polycarbonate resins, polyester resins, polyarylateresins, butyral resins, polystyrene resins, polyvinyl acetal resins,diallyl phthalate resins, acrylic resins, methacrylic resins, vinylacetate resins, phenolic resins, silicone resins, polysulfone resins,styrene-butadiene copolymer resins, alkyd resins, epoxy resins, urearesins, and vinyl chloride-vinyl acetate copolymer resins. Any of thesemay be used alone or in the form of a mixture or copolymer of two ormore types.

[0151] As a solvent used for a charge generation layer coating fluid, itmay be selected taking account of the binder resin to be used and thesolubility or dispersion stability of the charge-generating material. Asan organic solvent, usable are alcohols, sulfoxides, ketones, ethers,esters, aliphatic halogenated hydrocarbons or aromatic compounds.

[0152] To form the charge generation layer, the above charge-generatingmaterial may be well dispersed in the binder resin, which is used in a0.3- to 4-fold quantity, together with the solvent by means of ahomogenizer, an ultrasonic dispersion machine, a ball mill, a sand mill,an attritor or a roll mill, and the resultant dispersion is coated,followed by drying. The charge generation layer may preferably be formedin a layer thickness of 5 μm or less, and particularly preferably from0.01 μm to 1 μm.

[0153] To the charge generation layer, a sensitizer, an antioxidant, anultraviolet absorber and a plasticizer which may be of various types,and any known charge-generating material may also optionally be added.

[0154] The charge transport layer of the electrophotographicphotosensitive member of the present invention is formed of a binderresin with a charge-transporting material dissolved therein.

[0155] The charge-transporting material used in the electrophotographicphotosensitive member of the present invention may include triarylaminecompounds, hydrazone compounds, styryl compounds, stilbene compounds,pyrazoline compounds, oxazole compounds, thiazole compounds, andtriarylmethane compounds.

[0156] As the binder resin used to form the charge transport layer,preferable are polyacrylate resins, polystyrene resins, polyesterresins, polycarbonate resins, polyarylate resins, polysulfone resins,polyphenylene oxide resins, epoxy resins, polyurethane resins, alkydresins and unsaturated resins. Particularly preferred resins may includepolymethyl methacrylate resins, polystyrene resins,styrene-acrylonitrile copolymer resins, polycarbonate resins and diallylphthalate resins.

[0157] The charge transport layer may commonly be formed by coating asolution prepared by dissolving the above charge-transporting materialand binder resin in a solvent, followed by drying. Thecharge-transporting material and the binder resin may be mixed in aproportion of from about 2:1 to 1:2 in weight ratio.

[0158] As the solvent used in such a charge transport layer coatingsolution, usable are ketones such as acetone and methyl ethyl ketone;esters such as methyl acetate and ethyl acetate; ethers such asdimethoxymethane, tetrahydrofuran and dioxane; aromatic hydrocarbonssuch as toluene and xylene; and chlorine type hydrocarbons such aschlorobenzene, dichloromethane, chloroform and carbon tetrachloride.

[0159] When this coating solution is coated, coating methods asexemplified by dip coating, spray coating and spinner coating may beused. Also, the drying may be carried out at a temperature rangingpreferably from 10° C. to 200° C., and more preferably from 20° C. to150° C., for a time ranging preferably from 5 minutes to 5 hours, andmore preferably from 10 minutes to 2 hours, under air drying, drying atrest or vacuum drying.

[0160] The charge transport layer is kept electrically connected withthe above charge generation layer. It has the function to receive chargecarriers injected from the charge generation layer in the presence of anelectric field and at the same time transport these charge carriers tothe interface between it and its surface side. This charge transportlayer has a limit to the transporting of charge carriers, and hence itis not preferable to make the layer have a larger layer thickness thanis necessary. The charge transport layer may preferably have a layerthickness of from 5 μm to 40 μm, and particularly preferably from 7 μmto 30 μm.

[0161] Where the hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention is used in thecharge transport layer, it may be used in place of thecharge-transporting material and binder resin described above. Thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention has both thefunction as a charge-transporting material and the function as a binderresin for itself alone. Hence, the function as an electrophotographicphotosensitive member is ensured even when only thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention is dissolved ina solvent to prepare a charge transport layer coating solution to formthe charge transport layer. If necessary, thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention and thecharge-transporting material and binder resin described above may alsobe used in the form of a mixture.

[0162] As the solvent used when the hydroxymethyl-group-containingphenolic compound having charge-transportable structure of the presentinvention is used in the charge transport layer, it may include alcoholssuch as methanol, ethanol, propanol and butanol; ketones such as acetoneand methyl ethyl ketone; esters such as methyl acetate, ethyl acetateand butyl acetate; ethers such as dimethoxymethane, tetrahydrofuran anddioxane; aromatic hydrocarbons such as toluene and xylene; and chlorinetype hydrocarbons such as chlorobenzene, chloroform and carbontetrachloride.

[0163] When the charge transport layer coating solution is coated, thesame coating methods as described above may be used. Also, the dryingmay be carried out at a temperature ranging preferably from 10° C. to200° C., and more preferably from 20° C. to 180° C., for a time rangingpreferably from 5 minutes to 5 hours, and more preferably from 10minutes to 2 hours, under air drying, drying at rest or vacuum drying.

[0164] The phenolic compound of the present invention may preferably bemade to undergo heat curing reaction at the same time the solvent isremoved, in the drying step after the charge transport layer coatingsolution has been coated.

[0165] The hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention is, underconditions of the drying after this coating, cross-linked bycondensation reaction the hydroxymethyl groups chiefly cause, andbecomes cured three-dimensionally, whereby the charge transport layercan be improved in strength as a film and can be endowed with a highdurability.

[0166] Where the charge transport layer is the surface layer of theelectrophotographic photosensitive member, the layer may be incorporatedwith, in addition to the hydroxymethyl-group-containing phenoliccompound having charge-transportable structure of the present invention,lubricating particles such as fluorine-atom-containing resin particlessuch as tetrafluoroethylene resin or vinylidene fluoride resinparticles, or silicone resin particles, silica particles or aluminaparticles by dispersing them, in order to improve durability, lubricity,toner transfer performance and so forth of the electrophotographicphotosensitive member.

[0167] To the charge transport layer, an antioxidant, an ultravioletabsorber, a plasticizer and any known charge-transporting material mayfurther optionally be added.

[0168] In the case when the charge transport layer is the surface layerof the electrophotographic photosensitive member, thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention may alsopreferably be in an amount of from 1% by weight to 100% by weight, andmore preferably from 50% by weight to 95% by weight, based on the totalweight of the charge transport layer.

[0169] Where the photosensitive layer is of the single-layer type, thecharge-generating material and the charge-transporting material aremixed in an any desired proportion, and the binder resin used in thecharge generation layer or charge transport layer is used together.These are dissolved or dispersed in a solvent to prepare a coatingfluid, and the coating fluid obtained is coated, followed by drying toform the layer. The one in which the charge-generating material and thecharge-transporting material have been put together and the binder resinmay preferably be mixed in a proportion of from 3:1 to 1:3.

[0170] As the solvent of such a single-layer type photosensitive layercoating fluid, the same one as that used when the charge generationlayer or charge transport layer described above is formed.

[0171] When the single-layer type photosensitive layer coating fluid iscoated, the same coating methods as described above may be used. Also,the drying may be carried out at a temperature ranging preferably from10° C. to 200° C., and more preferably from 20° C. to 180° C., for atime ranging preferably from 5 minutes to 5 hours, and more preferablyfrom 10 minutes to 2 hours, under air drying, drying at rest or vacuumdrying.

[0172] The phenolic compound of the present invention may preferably bemade to undergo heat curing reaction at the same time the solvent isremoved, in the drying step after the single-layer type photosensitivelayer coating fluid has been coated.

[0173] In the single-layer type photosensitive layer, too, it has alimit to the transporting of charge carriers, and hence it can not bemade to have a larger layer thickness than is necessary. Thesingle-layer type photosensitive layer may preferably have a layerthickness of from 5 μm to 40 μm, and particularly preferably from 7 μmto 30 μm.

[0174] Where the hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention is used in thesingle-layer type photosensitive layer, like the case when used in thecharge transport layer, it may be used in place of thecharge-transporting material and binder resin. Thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention has both thefunction of charge transport and the function as a binder resin. Hence,the single-layer type photosensitive layer can be film-formed withoutmixing any other resin.

[0175] However, like the foregoing, the hydroxymethyl-group-containingphenolic compound having charge-transportable structure of the presentinvention may be used in the form of its mixture with thecharge-transporting material and the binder resin. Other conditions mayalso be the same as those in the case when the charge transport layer isformed.

[0176] In the case of the single-layer type photosensitive layer, too,it may be incorporated with lubricating particles such asfluorine-atom-containing resin particles such as tetrafluoroethyleneresin or vinylidene fluoride resin particles, or silicone resinparticles, silica particles or alumina particles by dispersing them, inorder to improve durability, lubricity, toner transfer performance andso forth of the electrophotographic photosensitive member.

[0177] To the single-layer type photosensitive layer, an antioxidant, anultraviolet absorber, a plasticizer and any known charge-transportingmaterial may further optionally be added.

[0178] Where the single-layer type photosensitive layer is the surfacelayer the hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention may alsopreferably be in an amount of from 1% by weight to 95% by weight, andmore preferably from 10% by weight to 90% by weight, based on the totalweight of the single-layer type photosensitive layer.

[0179] Where the hydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention is used in thestate it is incorporated in the protective layer, a protective-layercoating solution containing the hydroxymethyl-group-containing phenoliccompound having charge-transportable structure of the present inventionmay be coated on the photosensitive layer, followed by drying and curingto provide the protective layer.

[0180] The protective layer containing thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention is athree-dimensionally cross-linked cured film, and hence can achieve asufficient durability even in a relatively small layer thickness. Also,the cured protective layer obtained has the function of chargetransport, and hence any increase in residual potential and anypotential variations at the time of running service which have been seenwhen conventional protective layers are provided may little occur. Thus,an electrophotographic photosensitive member can be provided whichmaintains stable image quality over a long period of time and does notcause any smeared images even when used over a long period of time in anenvironment of high temperature and high humidity.

[0181] Where the surface layer of the electrophotographic photosensitivemember is the protective layer, a protective-layer coating solutionprepared by dissolving or diluting the phenolic compound of the presentinvention in or with a solvent is coated on the photosensitive layer.After its coating, polymerization reaction takes place to form a curedprotective layer.

[0182] As the solvent used to prepare the protective-layer coatingsolution, it is required to well dissolve thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention, and ensure gooddispersibility for the lubricating particles or the like when they areused. It further must be a solvent which does not adversely affect thephotosensitive layer with which the protective-layer coating solution ordispersion is to come into contact.

[0183] Accordingly, usable as the solvent are alcohols such as methanol,ethanol and 2-propanol; ketones such as acetone and methyl ethyl ketone,esters such as methyl acetate, ethyl acetate and butyl acetate; etherssuch as dimethoxymethane, tetrahydrofuran and dioxane; aromatichydrocarbons such as toluene and xylene; and halogen type hydrocarbonssuch as chlorobenzene and dichloromethane, any of which may further beused in the form of a mixture. Of these, as solvents which are wellcapable of dissolving the hydroxymethyl-group-containing phenoliccompound having charge-transportable structure of the present inventionand do not adversely affect the photosensitive layer which is to standan underlying layer when the coating solution is coated, alcohols suchas methanol, ethanol and 2-propanol are more preferred.

[0184] In the protective layer of the electrophotographic photosensitivemember of the present invention, in addition to thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention, any knownphenolic resin or other resin used when the charge transport layer isformed may also be used in the form of a mixture in order to improvestrength of the protective layer. As the phenolic resin, any of knownnovolak resins, resol resins and so forth may be mixed. In order toimprove properties of the protective layer, in addition to thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention, any knowncharge-transporting material may also be used in the form of a mixture.As the charge-transporting material used in such a case, the one usedwhen the photosensitive layer is formed may be used.

[0185] The protective layer of the electrophotographic photosensitivemember of the present invention may be formed by any coating methodcommonly used, such as dip coating, spray coating, spinner coating,roller coating, Meyer bar coating and blade coating.

[0186] The protective layer may preferably have a layer thickness offrom 0.1 μmm to 10 μmm, and more preferably from 0.5 μmm to 7 μmm.

[0187] The protective layer, too, may be incorporated with lubricatingparticles such as fluorine-atom-containing resin particles such astetrafluoroethylene resin or vinylidene fluoride resin particles, orsilicone resin particles, silica particles or alumina particles bydispersing them, in order to improve durability, lubricity, tonertransfer performance and so forth of the electrophotographicphotosensitive member.

[0188] In the present invention, additives such as an antioxidant may beincorporated in the surface layer in order to prevent the surface layerfrom deteriorating because of adhesion of active substances such asozone and nitrogen oxides generated at the time of charging.

[0189] In the case when the protective layer is the surface layer of theelectrophotographic photosensitive member, thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure of the present invention may alsopreferably be in an amount of from 10% by weight to 100% by weight, andmore preferably from 50% by weight to 100% by weight, based on the totalweight of the protective layer.

[0190]FIG. 2 schematically illustrates the construction of anelectrophotographic apparatus provided with a process cartridge havingthe electrophotographic photosensitive member of the present invention.

[0191] In FIG. 2, reference numeral 11 denotes a drum-shapedelectrophotographic photosensitive member of the present invention,which is rotatingly driven around an axis 12 in the direction of anarrow at a stated peripheral speed. The electrophotographicphotosensitive member 11 is, in the course of its rotation, uniformlyelectrostatically charged on its periphery to a positive or negative,given potential through a (primary) charging means 13. Theelectrophotographic photosensitive member thus charged is then exposedto exposure light 14 emitted from an exposure means (not shown) for slitexposure or laser beam scanning exposure and intensity-modulatedcorrespondingly to time-sequential digital image signals of the intendedimage information. In this way, electrostatic latent imagescorresponding to the intended image information are successively formedon the periphery of the electrophotographic photosensitive member 11.

[0192] The electrostatic latent images thus formed are subsequentlydeveloped with toner by the operation of a developing means 15. Thetoner images thus formed and held on the surface of theelectrophotographic photosensitive member 11 are then successivelytransferred by the operation of a transfer means 16, to a transfermaterial 17 fed from a paper feed section (not shown) to the partbetween the electrophotographic photosensitive member 11 and thetransfer means 16 in the manner synchronized with the rotation of theelectrophotographic photosensitive member 11.

[0193] The transfer material 17 on which the toner images have beentransferred is separated from the surface of the electrophotographicphotosensitive member, is led through a fixing means 18, where the tonerimages are fixed, and is then put out of the apparatus as animage-formed material (a print or copy).

[0194] The surface of the electrophotographic photosensitive member 11from which images have been transferred is brought to removal of thetoner remaining after the transfer, through a cleaning means 19. Thus,its surface is cleaned. The electrophotographic photosensitive member isfurther subjected to charge elimination by pre-exposure light 20 emittedfrom a pre-exposure means (not shown), and then repeatedly used for theformation of images.

[0195] Incidentally, where the charging means 13 is a contact chargingmeans making use of a charging roller, the pre-exposure is notnecessarily required. Also, in an apparatus having construction in whichthe transfer residual toner is recycled, a cleanerless process may beused.

[0196] In the present invention, the apparatus may be constituted of acombination of plural components integrally joined as a processcartridge from among the constituents such as the aboveelectrophotographic photosensitive member 11, charging means 13,developing means 15, transfer means 16 and cleaning means 19 so that theprocess cartridge is detachably mountable to the main body of anelectrophotographic apparatus such as a copying machine or a laser beamprinter. For example, at least one of the charging means 13, thedeveloping means 15 and the cleaning means 19 may integrally besupported in a cartridge together with the electrophotographicphotosensitive member 11 to form a process cartridge that is detachablymountable to the main body of the apparatus through a guide means 22such as rails provided in the main body of the apparatus.

[0197] Where the electrophotographic apparatus is a copying machine or aprinter, the exposure light 14 is light reflected from, or transmittedthrough, an original, or light irradiated by the scanning of a laserbeam, the driving of an LED array or the driving of a liquid-crystalshutter array according to signals obtained by reading an originalthrough a sensor and converting the information into signals.

[0198] As the charging means 13, it may also include, in addition to theabove charging roller, a corona charging assembly, a brush chargingassembly, a magnetic-brush charging assembly and a blade chargingassembly.

[0199] As the developing means 15, it may also include a jumpingdeveloping assembly, a one-component contact developing assembly and atwo-component contact developing assembly.

[0200] As the transfer means 16, it may also include a roller transferassembly, a corona transfer assembly, a blade transfer assembly, a belttransfer assembly and an intermediate transfer member.

[0201] As the fixing means 18, it may also include a heat roller fixingassembly, a heat belt fixing assembly and a pressure roller fixingassembly.

[0202] As the cleaning means 19, it may also include a blade cleaner, aroller cleaner, a brush cleaner and a suction cleaner.

[0203] The electrophotographic photosensitive member of the presentinvention may be not only applied in electrophotographic copyingmachines, but also widely applied in the fields where electrophotographyis applied, e.g., laser beam printers, CRT printers, LED printers,facsimile machines, liquid-crystal printers, and laser platemaking.

[0204] The present invention is described below in greater detail bygiving specific working examples. Note that the present invention is byno means limited to these working examples. In the following workingexamples, “part(s)” refers to “part(s) by weight”.

SYNTHESIS EXAMPLES

[0205] Examples of how to synthesize the hydroxymethyl-group-containingphenolic compound having charge-transportable structure and resol resinhaving charge-transportable structure of the present invention are givenbelow.

Synthesis Example 1

[0206] 50 parts of the phenolic compound having structure represented bythe formula (P-5) was dissolved in a mixture of 250 parts of an aqueouspotassium hydroxide solution (10%) and 200 parts of methanol. To thesolution formed, 150 parts of formalin (37%) was dropwise added over aperiod of 1 hours.

[0207] After the reaction was completed, the reaction mixture wasintroduced into an aqueous sulfuric acid solution to effectneutralization, and the product was crystallized.

[0208] To the pasty precipitate obtained, ethyl acetate was added todissolve the precipitate, followed by washing with water four to fivetimes using a separating funnel.

[0209] Finally, the organic layer formed was taken out, to whichmagnesium sulfuric anhydride was added to effect dehydration, andthereafter the organic layer dehydrated was concentrated by means of anevaporator to obtain crude crystals of the product.

[0210] The crude crystals thus obtained were recrystallized with 40parts of methanol and 300 parts of diisopropyl ether to obtain thedesired product as white powder. The yield was 70%.

[0211] Its purity was measured by reversed-phase HPLC (high-performanceliquid chromatography) (column: Shodex C18-5B, trade name; availablefrom Showa Denko K.K.; solvent: methanol/water=80/20) and GPC (gelpermeation chromatography) (columns: TOSOH TSK Gourd Column HXL, TSKgelG2000HXL×2 and TSKgel G3000HXL×1, trade names; available from TosohCorporation; solvent: THF). Tetrahydroxymethyl unit (those having fourhydroxymethyl groups) content was found to be solvent: THF).Tetrahydroxymethyl unit (those having four hydroxymethyl groups) contentwas found to be 86%.

Synthesis Example 2

[0212] 50 parts of the phenolic compound having structure represented bythe formula (P-5) was dissolved in a mixture of 50 parts of ammoniawater (28%), 150 parts of methanol and 20 parts of triethylamine. To thesolution formed, 150 parts of formalin (37%) was dropwise added over aperiod of 30 minutes with stirring. Thereafter, the resultant reactionmixture was heated to 60° C. Keeping this temperature, reaction wascarried out for 24 hours with stirring.

[0213] After the reaction was completed, the reaction mixture wasconcentrated under reduced pressure. After the mixture came to increasein viscosity, 200 parts of methanol and 100 parts of water were added,and further the solvents were removed under reduced pressure. Thisprocedure was repeated twice, and the remaining amine catalyst wasremoved.

[0214] After the solvents were removed, methanol was added to theresultant viscous resin component to obtain a product as a resol resinvarnish having a solid content of 60% by weight. The varnish yield was77 parts.

[0215] The content of monomers and dimers was measured by the same GPCas that used in Synthesis Example 1. As the result, monomers were foundto be in a content of 70% and dimers 24% (as structural units of theraw-material phenolic compound).

Synthesis Example 3

[0216] In place of the phenolic compound having structure represented bythe formula (P-5) which was used in Synthesis Example 1, 50 parts of thephenolic compound having structure represented by the formula (P-15) wasmixed with 150 parts of an aqueous potassium hydroxide solution (10%)and 1,000 parts of methanol. The solution formed was heated to 50° C. todissolve the phenolic compound, and then 75 parts of formalin (37%) wasdropwise added over a period of 1 hour.

[0217] After the addition was completed, the reaction was carried out at50° C. for further 50 hours, and the post treatment was made in the samemanner as in Synthesis Example 1. The phenolic compound thus obtainedwas recrystallized in basically the same manner as in Synthesis Example1.

[0218] Namely, it was recrystallized with 10 parts of methanol and 250parts of diisopropyl ether to obtain the desired product as whitepowder. The yield was 56%.

[0219] Its purity was measured by the same HPLC and GPC as those used inSynthesis Example 1. The dihydroxymethyl unit content was found to be87%.

Synthesis Example 4

[0220] In place of the phenolic compound having structure represented bythe formula (P-5) which was used in Synthesis Example 2, 50 parts of thephenolic compound having structure represented by the formula (P-15) wasdissolved in a mixture of 50 parts of ammonia water (28%), 550 parts ofmethanol and 100 parts of triethylamine. To the solution formed, 75parts of formalin (37%) was dropwise added over a period of 30 minuteswith stirring. Thereafter, the resultant reaction mixture was heated to50° C. Keeping this temperature, reaction was carried out for 24 hourswith stirring.

[0221] That is, the procedure of Synthesis Example 2 was repeated exceptthat the phenolic compound was changed for the phenolic compound havingstructure represented by the formula (P-15). Thus, a novel resol resinof the present invention was synthesized.

[0222] The resol resin obtained was passed through the step of removingthe catalyst under reduced pressure in the same manner as in SynthesisExample 2. Then, methanol was added to obtain a product as a resol resinvarnish having a solid content of 60% by weight. The varnish yield was75 parts.

[0223] The content of monomers and dimers was measured by the same GPCas that used in Synthesis Example 1. As the result, monomers were foundto be in a content of 66% and dimers 28% (as structural units of theraw-material phenolic compound).

Synthesis Example 5

[0224] In place of the phenolic compound having structure represented bythe formula (P-5) which was used in Synthesis Example 1, 50 parts of thephenolic compound having structure represented by the formula (P-22) wasmixed with 250 parts of an aqueous potassium hydroxide solution (10%)and 200 parts of methanol. The solution formed was heated to 40° C. todissolve the phenolic compound, and then 150 parts of formalin (37%) wasdropwise added over a period of 1 hour.

[0225] After the addition was completed, the reaction was carried out at40° C. for further 36 hours, and the post treatment was made in the samemanner as in Synthesis Example 1. The phenolic compound thus obtainedwas recrystallized in basically the same manner as in SynthesisExample 1. Namely, it was recrystallized with 40 parts of methanol and320 parts of diisopropyl ether to obtain the desired product as whitepowder. The yield was 68%.

[0226] Its purity was measured by the same HPLC and GPC as those used inSynthesis Example 1. The tetrahydroxymethyl unit content was found to be88%.

Synthesis Example 6

[0227] In place of the phenolic compound having structure represented bythe formula (P-5) which was used in Synthesis Example 2, 50 parts of thephenolic compound having structure represented by the formula (P-22) wasdissolved in a mixture of 50 parts of ammonia water (28%), 150 parts ofmethanol and 20 parts of triethylamine. To the solution formed, 150parts of formalin (37%) was dropwise added over a period of 30 minuteswith stirring. Thereafter, the resultant reaction mixture was heated to50° C. Keeping this temperature, reaction was carried out for 24 hourswith stirring.

[0228] Except the foregoing, the procedure of Synthesis Example 2 wasrepeated to synthesize a novel resol resin of the present invention.

[0229] The resol resin obtained was passed through the step of removingthe catalyst under reduced pressure in the same manner as in SynthesisExample 2. Then, methanol was added to obtain a product as a resol resinvarnish having a solid content of 60% by weight. The varnish yield was76 parts.

[0230] The content of monomers and dimers was measured by the same GPCas that used in Synthesis Example 1. As the result, monomers were foundto be in a content of 52% and dimers 34% (as structural units of theraw-material phenolic compound).

Synthesis Example 7

[0231] In place of the phenolic compound having structure represented bythe formula (P-5) which was used in Synthesis Example 2, 50 parts of thephenolic compound having structure represented by the formula (P-26) wasdissolved in a mixture of 50 parts of ammonia water (28%), 250 parts ofmethanol and 20 parts of triethylamine. To the solution formed, 200parts of formalin (37%) was dropwise added over a period of 30 minuteswith stirring. Thereafter, the resultant reaction mixture was heated to50° C. Keeping this temperature, reaction was carried out for 16 hourswith stirring.

[0232] Except the foregoing, the procedure of Synthesis Example 2 wasrepeated to synthesize a novel resol resin of the present invention.

[0233] The resol resin obtained was passed through the step of removingthe catalyst under reduced pressure in the same manner as in SynthesisExample 2. Then, methanol was added to obtain a product as a resol resinvarnish having a solid content of 60% by weight. The varnish yield was78 parts.

[0234] The content of monomers and dimers was measured by the same GPCas that used in Synthesis Example 1. As the result, monomers were foundto be in a content of 46% and dimers 38% (as structural units of theraw-material phenolic compound).

Synthesis Example 8

[0235] In place of the phenolic compound having structure represented bythe formula (P-5) which was used in Synthesis Example 2, 50 parts of thephenolic compound having structure represented by the formula (P-32) wasdissolved in a mixture of 50 parts of ammonia water (28%), 450 parts ofmethanol and 30 parts of triethylamine. To the solution formed, 250parts of formalin (37%) was dropwise added over a period of 30 minuteswith stirring. Thereafter, the resultant reaction mixture was heated to50° C. Keeping this temperature, reaction was carried out for 12 hourswith stirring.

[0236] Except the foregoing, the procedure of Synthesis Example 2 wasrepeated to synthesize a novel resol resin having charge-transportableof the present invention.

[0237] The resol resin obtained was passed through the step of removingthe catalyst under reduced pressure in the same manner as in SynthesisExample 2. Then, methanol was added to obtain a product as a resol resinvarnish having a solid content of 60% by weight. The varnish yield was77 parts.

[0238] The content of monomers and dimers was measured by the same GPCas that used in Synthesis Example 1. As the result, monomers were foundto be in a content of 50% and dimers 35% (as structural units of theraw-material phenolic compound).

Example 1

[0239] An aluminum cylinder of 357.5 mm in length and 30 mm in diameter(JISA3003 aluminum alloy) was used as a support. On this support, amethanol solution of 5% by weight of a polyamide resin (trade name:AMILAN CM8000; available from Toray Industries, Inc.) was coated by dipcoating, followed by drying to form an intermediate layer with a layerthickness of 0.5 μm.

[0240] Next, 4 parts of an oxytitanium phthalocyanine pigment havingstructure represented by the following formula:

[0241] and being of a crystal form having strong peaks at Bragg's angles(2θ±0.20) of 9.00 and 27.10 in the CuKα characteristic X-raydiffraction, 2 parts of polyvinyl butyral resin (trade name: S-LEC BX-1;available from Sekisui Chemical Co., Ltd.) and 110 parts ofcyclohexanone were dispersed for 4.5 hours by means of a sand mill usingglass beads of 1 mm in diameter, followed by dilution with 130 parts ofethyl acetate to prepare a charge generation layer coating dispersion.This charge generation layer coating dispersion was coated on the aboveintermediate layer by dipping, followed by drying to form a chargegeneration layer with a layer thickness of 0.18 μm.

[0242] Next, 7.5 parts of a charge-transporting material havingstructure represented by the following formula:

[0243] and 10 parts of a bisphenol-Z type polycarbonate (trade name:IUPILON Z-200; available from Mitsubishi Gas Chemical Company, Inc.)were dissolved in a mixed solvent of 60 parts of monochlorobenzene and20 parts of dimethoxymethane. The solution thus prepared was coated onthe above charge generation layer by dipping, followed by hot-air dryingat 110° C. for 1 hour to form a charge transport layer with a layerthickness of 17 μm.

[0244] Next, for a protective layer, 30 parts of thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure which was obtained in Synthesis Example 1and 70 parts of ethanol were mixed, and then stirred for 2 hours toeffect dissolution to prepare a protective-layer coating solution. Usingthis protective-layer coating solution, a film was formed on the abovecharge transport layer by dip coating, followed by hot-air drying at145° C. for 1 hour to form a protective layer with a layer thickness of3 μm. Thus, an electrophotographic photosensitive member was produced.

[0245] The protective-layer coating solution had good coatingproperties, and the protective layer formed was an unevenness-free,uniform film.

[0246] To evaluate the cure characteristics of the protective layerformed, a wiper made of paper was soaked with methyl ethyl ketone, andthen made to adhere to the film surface and rub the surface in such away as to rub the chemical into the film, where how the film dissolvedwas observed. As the result, the protective layer was not scrapable off,and was found to have completely cured.

[0247] The electrophotographic photosensitive member produced in thisway was set in an electrophotographic apparatus to make evaluation.

[0248] To evaluate electrophotographic performance, theelectrophotographic photosensitive member was set in a modified machineof a laser electrostatic-transfer system copying machine (trade name:GP-405; manufacture by CANON INC.). As sensitivity, its surface was soset as to be charged at a dark-area potential of −700 V, and was exposedto laser light of 780 nm in wavelength, where the amount of lightnecessary for the potential of −700 V to attenuate to −200 V wasmeasured to examine the sensitivity Δ500 (μJ/cm²). The potential whenexposed to light with energy of 20 μJ/cm² was also measured as residualpotential Vr (V).

[0249] In addition, as evaluation by image reproduction running on30,000 sheets using the same copying machine, image quality wasevaluated and abrasion level was measured at the initial stage and afterthe running.

[0250] The image quality was evaluated on items of gradationreproducibility, any scratches having appeared on images, any fog havingappeared on white-background images, and changes in density.

[0251] The abrasion level was measured with an eddy-current layerthickness measuring device manufactured by Fischer Co., Germany.

[0252] To evaluate also potential variations after use in the running,the sensitivity Δ500 and the residual potential Vr were measured afterthe image reproduction running on 30,000 sheets.

[0253] To make evaluation on smeared images which may appear when usedin running in an environment of high temperature and high humidity, theelectrophotographic photosensitive member described above was set in theabove copying machine to make a running test in an environment of 30°C./80%RH. Whether or not the smeared images appeared at what point oftime in the course of the running test made up to 30,000 sheets wasobserved.

[0254] The results of observation are shown in Table 1.

Example 2

[0255] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0256] Next, for a protective layer, in place of the protective layer ofExample 1, 50 parts of the varnish of the resol resin havingcharge-transportable structure which was obtained in Synthesis Example 2(solid content: 60% by weight) and 50 parts of ethanol were mixed, andthen stirred for 2 hours to effect dissolution to prepare aprotective-layer coating solution. Using this protective-layer coatingsolution, a film was formed on the above charge transport layer by dipcoating in the same manner as in Example 1, followed by hot-air dryingat 145° C. for 1 hour to form a protective layer with a layer thicknessof 3 μm. The protective-layer coating solution had good coatingproperties, and the protective layer formed was an unevenness-free,uniform film.

[0257] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Example 3

[0258] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0259] Next, for a protective layer, in place of the protective layer ofExample 1, 24 parts of the hydroxymethyl-group-containing phenoliccompound having charge-transportable structure which was obtained inSynthesis Example 3, 10 parts of resol type phenolic resin (trade name:PL-4852; available from Gun-ei Chemical Industry Co., Ltd.)(solidcontent: 60% by weight) and 66 parts of ethanol were mixed, and thenstirred for 2 hours to effect dissolution to prepare a protective-layercoating solution. Using this protective-layer coating solution, a filmwas formed on the above charge transport layer by dip coating in thesame manner as in Example 1, followed by hot-air drying at 145° C. for 1hour to form a protective layer with a layer thickness of 3 μm. Theprotective-layer coating solution had good coating properties, and theprotective layer formed was an unevenness-free, uniform film.

[0260] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Example 4

[0261] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0262] Next, for a protective layer, in place of the protective layer ofExample 1, 40 parts of the varnish of the resol resin havingcharge-transportable structure which was obtained in Synthesis Example 4(solid content: 60% by weight), 10 parts of resol type phenolic resin(trade name: PL-4852; available from Gun-ei Chemical Industry Co.,Ltd.)(solid content: 60% by weight) and 50 parts of ethanol were mixed,and then stirred for 2 hours to effect dissolution to prepare aprotective-layer coating solution. Using this protective-layer coatingsolution, a film was formed on the above charge transport layer by dipcoating in the same manner as in Example 1, followed by hot-air dryingat 145° C. for 1 hour to form a protective layer with a layer thicknessof 3 μm. The protective-layer coating solution had good coatingproperties, and the protective layer formed was an unevenness-free,uniform film.

[0263] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Example 5

[0264] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0265] Next, for a protective layer, in place of the protective layer ofExample 1, 30 parts of the hydroxymethyl-group-containing phenoliccompound having charge-transportable structure which was obtained inSynthesis Example 5 and 70 parts of ethanol were mixed, and then stirredfor 2 hours to effect dissolution to prepare a protective-layer coatingsolution. Using this protective-layer coating solution, a film wasformed on the above charge transport layer by dip coating in the samemanner as in Example 1, followed by hot-air drying at 145° C. for 1 hourto form a protective layer with a layer thickness of 3 μm. Theprotective-layer coating solution had good coating properties, and theprotective layer formed was an unevenness-free, uniform film.

[0266] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Example 6

[0267] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0268] Next, for a protective layer, in place of the protective layer ofExample 1, 50 parts of the varnish of the resol resin havingcharge-transportable structure which was obtained in Synthesis Example 6(solid content: 60% by weight) and 50 parts of ethanol were mixed, andthen stirred for 2 hours to effect dissolution to prepare aprotective-layer coating solution. Using this protective-layer coatingsolution, a film was formed on the above charge transport layer by dipcoating in the same manner as in Example 1, followed by hot-air dryingat 145° C. for 1 hour to form a protective layer with a layer thicknessof 3 μm. The protective-layer coating solution had good coatingproperties, and the protective layer formed was an unevenness-free,uniform film.

[0269] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Example 7

[0270] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0271] Next, for a protective layer, in place of the protective layer ofExample 1, 50 parts of the varnish of the resol resin havingcharge-transportable structure which was obtained in Synthesis Example 7(solid content: 60% by weight) and 50 parts of ethanol were mixed, andthen stirred for 2 hours to effect dissolution to prepare aprotective-layer coating solution Using this protective-layer coatingsolution, a film was formed on the above charge transport layer by dipcoating in the same manner as in Example 1, followed by hot-air dryingat 145° C. for 1 hour to form a protective layer with a layer thicknessof 3 μm. The protective-layer coating solution had good coatingproperties, and the protective layer formed was an unevenness-free,uniform film.

[0272] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Example 8

[0273] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0274] Next, for a protective layer, in place of the protective layer ofExample 1, 50 parts of the varnish of the resol resin havingcharge-transportable structure which was obtained in Synthesis Example 8(solid content: 60% by weight) and 50 parts of ethanol were mixed, andthen stirred for 2 hours to effect dissolution to prepare aprotective-layer coating solution. Using this protective-layer coatingsolution, a film was formed on the above charge transport layer by dipcoating in the same manner as in Example 1, followed by hot-air dryingat 145° C. for 1 hour to form a protective layer with a layer thicknessof 3 μm. The protective-layer coating solution had good coatingproperties, and the protective layer formed was an unevenness-free,uniform film.

[0275] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Example 9

[0276] On the same aluminum cylinder as that of Example 1, the sameintermediate layer and charge generation layer as those of Example 1were formed by coating.

[0277] Next, for a charge transport layer, in place of the chargetransport layer of Example 1, 12.5 parts of thehydroxymethyl-group-containing phenolic compound havingcharge-transportable structure which was obtained in Synthesis Example 3and 5 parts of a bisphenol-Z type polycarbonate resin (trade name:IUPILON Z-200; available from Mitsubishi Gas Chemical Company, Inc.)were dissolved in a mixed solvent of 40 parts of 1,4-dioxane and 32parts of dimethoxymethane. The solution thus prepared was dip-coated onthe above charge generation layer, followed by hot-air drying at 145° C.for 1 hour to form a charge transport layer with a layer thickness of 20μm.

[0278] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Comparative Example 1

[0279] On the same aluminum cylinder as that of Example 1, the sameintermediate layer and charge generation layer as those of Example 1were formed by coating.

[0280] Next, for a charge transport layer, the same charge transportlayer coating solution of Example 1 was dip-coated on the above chargegeneration layer, followed by hot-air drying at 110° C. for 1 hour toform a charge transport layer with a layer thickness of 30 μm.

[0281] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

Comparative Example 2

[0282] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0283] Next, for a protective layer, 50 parts of treated tin oxideparticles by surface-treating (amount of treatment: 7%) 100 parts ofantimony-doped tin oxide particles with an average particle diameter of0.02 μm (trade name: T-1; available from Mitsubishi Material Co., Ltd.)with 7 parts of a fluorine-atom-containing compound (trade name:LS-1090; available from Shin-Etsu Silicone Co., Ltd.) having structurerepresented by the following formula:

[0284] and 150 parts of ethanol were dispersed by means of a sand millfor 60 hours, and thereafter 20 parts of polytetrafluoroethyleneparticles (average particle diameter: 0.18 μm) were further added,followed by further dispersion for 8 hours. Thereafter, 30 parts of anacrylic resin monomer having structure represented by the followingformula:

[0285] and 2 parts of 2-methylthioxanthone as a photopolymerizationinitiator was added and dissolved to prepare a protective-layer coatingdispersion.

[0286] This protective-layer coating dispersion was dip-coated on theabove charge transport layer to form a film, which was subsequentlyphotocured at a light intensity of 800 mW/cm² for 60 seconds by means ofa high-pressure mercury lamp, followed by hot-air drying at 120° C. for2 hours to form a protective layer with a layer thickness of 3 μm.

[0287] Except the forgoing, the procedure of Example 1 was repeated toproduce an electrophotographic photosensitive member. Evaluation wasmade in the same way. The results of observation are shown in Table 1.

Comparative Example 3

[0288] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0289] Next, for a protective layer, a solution prepared by mixing 50parts of resol type phenolic resin (trade name: PL-4852; available fromGun-ei Chemical Industry Co., Ltd.)(solid content: 60% by weight) and 50parts of ethanol was dip-coated as a protective layer coating solutionon the charge transport layer, followed by hot-air drying at 145° C. for1 hour to form a protective layer with a layer thickness of 3 μm.

[0290] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0291] This electrophotographic photosensitive member had so lowsensitivity and so high residual potential that only a low image densitywas achievable, which was not on the level tolerable for the imagereproduction running test.

Comparative Example 4

[0292] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0293] Next, for a protective layer, a solution prepared by mixing 30parts of a phenolic compound having structure represented by thefollowing formula:

[0294] and having no charge-transportable structure and 70 parts ofethanol was dip-coated as a protective layer coating solution on thecharge transport layer, followed by hot-air drying at 145° C. for 1 hourto form a protective layer with a layer thickness of 3 μm.

[0295] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0296] This electrophotographic photosensitive member had so highresidual potential that only a low image density was achievable, whichwas not on the level tolerable for the image reproduction running test.

Comparative Example 5

[0297] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0298] Next, a solution prepared by mixing 30 parts of the phenoliccompound having structure represented by the formula (P-22) and 70 partsof ethanol was dip-coated as a coating solution on the charge transportlayer, followed by hot-air drying at 145° C. for 1 hour to form aprotective layer with a layer thickness of 3 μm.

[0299] To evaluate the cure characteristics of the layer formed, a wipermade of paper was soaked with methyl ethyl ketone, and then made toadhere to the film surface and rub the surface in such a way as to rubthe chemical into the film, where how the film dissolved was observed.As the result, the film on the charge transport layer was scrapable offwith ease, and was found to have not cured.

[0300] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0301] Since the layer at the surface of this electrophotographicphotosensitive member did not cure, the layer at the surface was soonscraped off after the running was started. During the running, thecharge transport layer came to the outermost surface layer to becomeworn away. The running on 30,000 sheets like that in Example 1 was notachievable, and the charge transport layer became thinner to come lowerthan the serviceable limit, so that the image reproduction became poor.

Comparative Example 6

[0302] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0303] Next, like a protective layer, a solution prepared by mixing 30parts of a phenolic compound having structure represented by thefollowing formula:

[0304] 60 parts of ethanol and 10 parts of methyl ethyl ketone wasdip-coated as a coating solution on the charge transport layer, followedby hot-air drying at 145° C. for 1 hour to form a layer with a layerthickness of 3 μm.

[0305] To evaluate the cure characteristics of the layer formed, a wipermade of paper was soaked with methyl ethyl ketone, and then made toadhere to the film surface and rub the surface in such a way as to rubthe chemical into the film, where how the film dissolved was observed.As the result, the film on the charge transport layer was scrapable offwith ease, and was found to have not cured.

[0306] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0307] Since the layer at the surface of this electrophotographicphotosensitive member did not cure, the layer at the surface was soonscraped off after the running was started. During the running, thecharge transport layer came to the outermost surface layer to becomeworn away. The running on 30,000 sheets like that in Example 1 was notachievable, and the charge transport layer became thinner to come lowerthan the serviceable limit, so that the image reproduction became poor.

Comparative Example 7

[0308] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0309] Next, like a protective layer, a solution prepared by mixing 4parts of a phenolic compound having structure represented by thefollowing formula:

[0310] and 96 parts of cyclohexanone was spray-coated as a coatingsolution on the charge transport layer, followed by hot-air drying at145° C. for 1 hour to form a layer with a layer thickness of 3 μm.

[0311] To evaluate the cure characteristics of the layer formed, a wipermade of paper was soaked with methyl ethyl ketone, and then made toadhere to the film surface and rub the surface in such a way as to rubthe chemical into the film, where how the film dissolved was observed.As the result, the film on the charge transport layer was scrapable offwith ease, and was found to have not cured.

[0312] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0313] Since the layer at the surface of this electrophotographicphotosensitive member did not cure, the layer at the surface was soonscraped off after the running was started. During the running, thecharge transport layer came to the outermost surface layer to becomeworn away. The running on 30,000 sheets like that in Example 1 was notachievable, and the charge transport layer became thinner to come lowerthan the serviceable limit, so that the image reproduction became poor.

Comparative Example 8

[0314] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0315] Next, like a protective layer, a solution prepared by mixing 30parts of a phenolic compound having structure represented by thefollowing formula:

[0316] and 70 parts of methanol was dip-coated as a coating solution onthe charge transport layer, followed by hot-air drying at 145° C. for 1hour to form a layer with a layer thickness of 3 μm.

[0317] To evaluate the cure characteristics of the layer formed, a wipermade of paper was soaked with methyl ethyl ketone, and then made toadhere to the film surface and rub the surface in such a way as to rubthe chemical into the film, where how the film dissolved was observed.As the result, the film on the charge transport layer was scrapable offwith ease, and was found to have not cured.

[0318] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0319] Since the layer at the surface of this electrophotographicphotosensitive member did not cure, the layer at the surface was soonscraped off after the running was started. During the running, thecharge transport layer came to the outermost surface layer to becomeworn away. The running on 30,000 sheets like that in Example 1 was notachievable, and the charge transport layer became thinner to come lowerthan the serviceable limit, so that the image reproduction became poor.

Comparative Example 9

[0320] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0321] Next, like a protective layer, a solution prepared by mixing 30parts of a hydroxymethyl-group-containing compound having structurerepresented by the following formula:

[0322] and 70 parts of methanol was dip-coated as a coating solution onthe charge transport layer, followed by hot-air drying at 145° C. for 1hour to form a layer with a layer thickness of 3 μm.

[0323] To evaluate the cure characteristics of the layer formed, a wipermade of paper was soaked with methyl ethyl ketone, and then made toadhere to the film surface and rub the surface in such a way as to rubthe chemical into the film, where how the film dissolved was observed.As the result, the film on the charge transport layer was scrapable offwith ease, and was found to have not cured.

[0324] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0325] Since the layer at the surface of this electrophotographicphotosensitive member did not cure, the layer at the surface was soonscraped off after the running was started. During the running, thecharge transport layer came to the outermost surface layer to becomeworn away. The running on 30,000 sheets like that in Example 1 was notachievable, and the charge transport layer became thinner to come lowerthan the serviceable limit, so that the image reproduction became poor.

Comparative Example 10

[0326] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0327] Next, like a protective layer, a solution prepared by mixing 30parts of a hydroxymethyl-group-containing compound having structurerepresented by the following formula:

[0328] and 70 parts of methanol was dip-coated as a coating solution onthe charge transport layer, followed by hot-air drying at 145° C. for 1hour to form a layer with a layer thickness of 3 μm.

[0329] To evaluate the cure characteristics of the layer formed, a wipermade of paper was soaked with methyl ethyl ketone, and then made toadhere to the film surface and rub the surface in such a way as to rubthe chemical into the film, where how the film dissolved was observed.As the result, the film on the charge transport layer was scrapable offwith ease, and was found to have not cured.

[0330] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1.

[0331] Since the layer at the surface of this electrophotographicphotosensitive member did not cure, the layer at the surface was soonscraped off after the running was started. During the running, thecharge transport layer came to the outermost surface layer to becomeworn away. The running on 30,000 sheets like that in Example 1 was notachievable, and the charge transport layer became thinner to come lowerthan the serviceable limit, so that the image reproduction became poor.

Comparative Example 11

[0332] On the same aluminum cylinder as that of Example 1, the sameintermediate layer, charge generation layer and charge transport layeras those of Example 1 were formed by coating.

[0333] Next, a solution prepared by dissolving 3 parts of the phenoliccompound having structure represented by the formula (P-5) and 4 partsof a solution of polyisocyanate (solid content: 67% by weight) havingstructure represented by the following formula:

[0334] in 120 parts of cyclohexanone was spray-coated as a coatingsolution on the charge transport layer, followed by drying at roomtemperature for 10 minutes and thereafter hot-air drying at 150° C. for1 hour to form a layer with a layer thickness of 3 μm.

[0335] To evaluate the cure characteristics of the layer formed, a wipermade of paper was soaked with methyl ethyl ketone, and then made toadhere to the film surface and rub the surface in such a way as to rubthe chemical into the film, where how the film dissolved was observed.As the result, the film on the charge transport layer was not scrapableoff with ease, and was found to have cured to a certain degree althoughnot comparable to the surface layers of the electrophotographicphotosensitive member of Examples.

[0336] The electrophotographic photosensitive member thus obtained wasevaluated in the same manner as in Example 1. The results of observationare shown in Table 1. TABLE 1 Initial stage After 30,000-sheet runningResid- Resid- Cure Sensi- ual Sensi- ual Abra- charac- tivity poten-tivity poten- sion Smeared images tens- Δ500 tial Vr Δ500 tial Vr levelImage in environment of tics (μJ/cm²) (−V) (μJ/cm²) (−V) (μm) evaluation30° C./80% RH Example:  1 Good. 0.28 35 0.29 40 0.9 No image No smearedimages defects. up to 30,000 sheets.  2 Good. 0.30 33 0.31 38 1.0 Noimage No smeared images defects. up to 30,000 sheets.  3 Good. 0.29 290.31 33 1.1 No image No smeared images defects. up to 30,000 sheets.  4Good. 0.29 33 0.32 37 1.2 No image No smeared images defects. up to30,000 sheets.  5 Good. 0.28 35 0.30 39 0.8 No image No smeared imagesdefects. up to 30,000 sheets.  6 Good. 0.28 36 0.31 39 0.8 No image Nosmeared images defects. up to 30,000 sheets.  7 Good. 0.32 37 0.33 391.0 No image No smeared images defects. up to 30,000 sheets.  8 Good.0.30 32 0.32 33 0.9 No image No smeared images defects. up to 30,000sheets.  9 Good. 0.34 46 0.38 51 5.2 No image No smeared imagesComparative Example:  1 — 0.26 22 0.40 17 19   Scratching, Smearedimages image density begin to occur on decrease, about 26,000 sheets.poor highlight gradation.  2 Poor. 0.47 37 0.32 83 1.7 Smeared images,Smeared images image density begin to occur at decrease, the initialstage. poor dot re- producibility.  3 Poor. 0.76 187 — — — Images arenot — reproducible.  4 Poor. — 263 — — — Sensitivity is — notmeasurable, images are not reproducible.  5 Poor. — — — — — Notevaluable. —  6 Poor. — — — — — Not evaluable. —  7 Poor. — — — — — Notevaluable. —  8 Poor. — — — — — Not evaluable. —  9 Poor. — — — — — Notevaluable. — 10 Poor. — — — — — Not evaluable. — 11 Poor a 0.44 73 0.56105 2.9 Scratching, Smeared images little image density begin to occuron decrease, about 8,000 sheets. poor highlight gradation.

[0337] According to the present invention, it is possible to provide anovel phenolic compound and a novel resol resin which are able to endowelectrophotographic photosensitive members with excellent properties(surface properties) to improve durability to the occurrence of wear andscratches, lessen residual-potential increase and potential variations,and maintain high-grade image quality over a long period of time, andalso provide cured products thereof.

[0338] According to the present invention, it is also possible toprovide an electrophotographic photosensitive member having a surfacelayer containing the above novel phenolic compound or novel resol resin,i.e., an electrophotographic photosensitive member which has a highdurability to the occurrence of wear and scratches, has smallresidual-potential increase and potential variations, can maintainhigh-grade image quality over a long period of time and does not causeany smeared images when used over a long period of time in anenvironment of high temperature and high humidity; and a processcartridge and an electrophotographic apparatus which have such anelectrophotographic photosensitive member.

What is claimed is:
 1. A phenolic compound comprising a compound havinga plurality of substituted hydroxyphenyl groups and charge-transportablestructure; at least one of said substituted hydroxyphenyl groups havingat least one hydroxymethyl group as a substituent.
 2. The phenoliccompound according to claim 1, wherein at least one of said substitutedhydroxyphenyl groups is a substituted p-hydroxyphenyl group.
 3. Thephenolic compound according to claim 1, wherein at least one of saidhydroxymethyl groups is linked at the position which is the o-positionin respect to any of the hydroxyl groups of the substitutedhydroxyphenyl groups having a hydroxymethyl group as a substituent. 4.The phenolic compound according to claim 1, wherein saidcharge-transportable structure is triarylamine structure.
 5. Thephenolic compound according to claim 1, which is a phenolic compoundhaving structure represented by any one of the following Formulas (1) to(5)

wherein R¹¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; R¹² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar¹¹ andAr¹² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar¹³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; letter symbols m and n are eachindependently 0 or 1; and X¹¹ to X¹⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX¹¹ to X¹⁴ is a hydroxymethyl group;

wherein R²¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar²¹ and Ar²² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R²¹; a letter symbol p is 0 or 1; and X²¹ andX²² each independently represent a hydrogen atom or a hydroxymethylgroup, provided that at least one of X²¹ and X²² is a hydroxymethylgroup;

wherein R³¹ and R³² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar³¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR³¹ may combine to form a ring via R³¹; the two benzene rings linked viaR³² may combine to form a ring via R³²; letter symbols q and r are eachindependently 0 or 1; and X³¹ to X³⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX³¹ to X³⁴ is a hydroxymethyl group;

wherein R⁴¹ to R⁴³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁴¹ may combine to form a ring via R⁴¹; the twobenzene rings linked via R⁴² may combine to form a ring via R⁴²; the twobenzene rings linked via R⁴³ may combine to form a ring via R⁴³; lettersymbols s, t and u are each independently 0 or 1; and X⁴¹ to X⁴⁶ eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁴¹ to X⁴⁶ is a hydroxymethyl group; and

wherein R⁵² represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Z⁵¹ and Z⁵² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z⁵¹ and the benzene ring having Z⁵² maycombine via Z⁵¹ or Z⁵² to form a ring; a letter symbol v is 0 or 1; aletter symbol w is an integer of 1 to 4; and X⁵¹ and X⁵² eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁵¹ and X⁵² is a hydroxymethyl group.
 6. Aresol resin comprising a resin obtained by allowing a phenolic compoundhaving hydroxyphenyl groups and charge-transportable structure, to reactwith formaldehyde in the presence of a basic catalyst; said resin havingcharge-transportable structure.
 7. The resol resin according to claim 6,wherein at least one of said hydroxyphenyl groups is a p-hydroxyphenylgroup.
 8. The resol resin according to claim 6, wherein saidcharge-transportable structure is triarylamine structure.
 9. The resolresin according to claim 6, wherein said phenolic compound havinghydroxyphenyl groups and charge-transportable structure has structurerepresented by any one of the following Formulas (6) to (10):

wherein R⁶¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched. R⁶² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar⁶¹ andAr⁶² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar⁶³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; and letter symbols m′ and n′ are eachindependently 0 or 1;

wherein R⁷¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar⁷¹ and Ar⁷² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R⁷¹; and a letter symbol p′ is 0 or 1;

wherein R⁸¹ and R⁸² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar⁸¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR⁸¹ may combine to form a ring via R⁸¹; the two benzene rings linked viaR⁸² may combine to form a ring via R⁸²; and letter symbols q′ and r′ areeach independently 0 or 1;

wherein R⁹¹ to R⁹³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁹¹ may combine to form a ring via R⁹¹; the twobenzene rings linked via R⁹² may combine to form a ring via R⁹²; the twobenzene rings linked via R⁹³ may combine to form a ring via R⁹³; lettersymbols s′, t′ and u′ are each independently 0 or 1; and

wherein R¹⁰² represents a divalent hydrocarbon group having 1 to 8carbon atoms and which may be branched; Z¹⁰¹ and Z¹⁰² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z¹⁰¹ and the benzene ring having Z¹⁰² maycombine via Z¹⁰¹ or Z¹⁰² to form a ring; a letter symbol v′ is 0 or 1;and a letter symbol w′ is an integer of 1 to
 4. 10. The resol resinaccording to claim 6, wherein said basic catalyst is an amine catalyst.11. The resol resin according to claim 10, wherein said amine catalystis a tertiary alkylamine.
 12. The resol resin according to claim 6,wherein said basic catalyst is a catalyst containing an alkali metal ora catalyst containing an alkaline earth metal.
 13. A cured product of aphenolic compound, comprising a cured product obtained by curing aphenolic compound having a hydroxymethyl group, wherein; said phenoliccompound is a phenolic compound having a plurality of substitutedhydroxyphenyl groups and charge-transportable structure; at least one ofsaid substituted hydroxyphenyl groups having at least one hydroxymethylgroup as a substituent.
 14. The cured product of a phenolic compoundaccording to claim 13, wherein at least one of said substitutedhydroxyphenyl groups is a substituted p-hydroxyphenyl group.
 15. Thecured product of a phenolic compound according to claim 13 or 14,wherein at least one of said hydroxymethyl groups is linked at theposition which is the o-position in respect to any of the hydroxylgroups of the substituted hydroxyphenyl groups having a hydroxymethylgroup as a substituent.
 16. The cured product of a phenolic compoundaccording to claim 13, wherein said charge-transportable structure istriarylamine structure.
 17. The cured product of a phenolic compoundaccording to claim 13, wherein said phenolic compound has structurerepresented by any one of the following Formulas (1) to (5):

wherein R¹¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; R¹² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar¹¹ andAr¹² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar¹³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; letter symbols m and n are eachindependently 0 or 1; and X¹¹ to X¹⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX¹¹ to X¹⁴ is a hydroxymethyl group;

wherein R²¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar²¹ and Ar²² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R²¹; a letter symbol p is 0 or 1; and X²¹ andX²² each independently represent a hydrogen atom or a hydroxymethylgroup, provided that at least one of X²¹ and X²² is a hydroxymethylgroup;

wherein R³¹ and R³² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar³¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR³¹ may combine to form a ring via R³¹; the two benzene rings linked viaR³² may combine to form a ring via R³²; letter symbols q and r are eachindependently 0 or 1; and X³¹ to X³⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX³¹ to X³⁴ is a hydroxymethyl group;

wherein R⁴¹ to R⁴³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁴¹ may combine to form a ring via R⁴¹; the twobenzene rings linked via R⁴² may combine to form a ring via R⁴²; the twobenzene rings linked via R⁴³ may combine to form a ring via R⁴³; lettersymbols s, t and u are each independently 0 or 1; and X⁴¹ to X⁴⁶ eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁴¹ to X⁴⁶ is a hydroxymethyl group; and

wherein R⁵² represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Z⁵¹ and Z⁵² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z⁵¹ and the benzene ring having Z⁵² maycombine via Z⁵¹ or Z⁵² to form a ring; a letter symbol v is 0 or 1; aletter symbol w is an integer of 1 to 4; and X⁵¹ and X⁵² eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁵¹ and X⁵² is a hydroxymethyl group. 18.A cured product of a resol resin, comprising a cured product obtained bycuring a resol resin, wherein; said resol resin is a resol resinobtained by allowing a phenolic compound having hydroxyphenyl groups andcharge-transportable structure, to react with formaldehyde in thepresence of a basic catalyst; said resol resin havingcharge-transportable structure.
 19. The cured product of a resol resinaccording to claim 18, wherein at least one of said hydroxyphenyl groupsis a p-hydroxyphenyl group.
 20. The cured product of a resol resinaccording to claim 18, wherein said charge-transportable structure istriarylamine structure.
 21. The cured product of a resol resin accordingto claim 18, wherein said phenolic compound having charge-transportablestructure has structure represented by any one of the following Formulas(6) to (10):

wherein R⁶¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; R⁶² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar⁶¹ andAr⁶² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar⁶³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; and letter symbols m′ and n′ are eachindependently 0 or 1;

wherein R⁷¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar⁷¹ and Ar⁷² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R⁷¹; and a letter symbol p′ is 0 or 1;

wherein R⁸¹ and R⁸² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar⁸¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR⁸¹ may combine to form a ring via R⁸¹; the two benzene rings linked viaR⁸² may combine to form a ring via R⁸²; and letter symbols q′ and r′ areeach independently 0 or 1;

wherein R⁹¹ to R⁹³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁹¹ may combine to form a ring via R⁹¹; the twobenzene rings linked via R⁹² may combine to form a ring via R⁹²; the twobenzene rings linked via R⁹³ may combine to form a ring via R⁹³; lettersymbols s′, t′ and u′ are each independently 0 or 1; and

wherein R¹⁰² represents a divalent hydrocarbon group having 1 to 8carbon atoms and which may be branched; Z¹⁰¹ and Z¹⁰² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z¹⁰¹ and the benzene ring having Z¹⁰² maycombine via Z¹⁰¹ or Z¹⁰² to form a ring; a letter symbol v′ is 0 or 1;and a letter symbol w′ is an integer of 1 to
 4. 22. The cured product ofa resol resin according to claim 18, wherein said basic catalyst is anamine catalyst.
 23. The cured product of a resol resin according toclaim 22, wherein said amine catalyst is a tertiary alkylamine.
 24. Thecured product of a resol resin according to claim 18, wherein said basiccatalyst is a catalyst containing an alkali metal or a catalystcontaining an alkaline earth metal.
 25. An electrophotographicphotosensitive member comprising a support and provided thereon aphotosensitive layer, wherein; said electrophotographic photosensitivemember has a surface layer which contains a cured product of a phenoliccompound having a plurality of substituted hydroxyphenyl groups andcharge-transportable structure; at least one of said substitutedhydroxyphenyl groups having at least one hydroxymethyl group as asubstituent.
 26. The electrophotographic photosensitive member accordingto claim 25, wherein at least one of said substituted hydroxyphenylgroups is a substituted p-hydroxyphenyl group.
 27. Theelectrophotographic photosensitive member according to claim 25, whereinat least one of said hydroxymethyl groups is linked at the positionwhich is the o-position in respect to any of the hydroxyl groups of thesubstituted hydroxyphenyl groups having a hydroxymethyl group as asubstituent.
 28. The electrophotographic photosensitive member accordingto claim 25, wherein said charge-transportable structure is triarylaminestructure.
 29. The electrophotographic photosensitive member accordingto claim 25, wherein said phenolic compound has structure represented byany one of the following Formulas (1) to (5):

wherein R¹¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; R¹² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar¹¹ andAr¹² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar¹³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; letter symbols m and n are eachindependently 0 or 1; and X¹¹ to X¹⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX¹¹, to X¹⁴ is a hydroxymethyl group;

wherein R²¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar²¹ and Ar²² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R²¹; a letter symbol p is 0 or 1; and X²¹ andX²² each independently represent a hydrogen atom or a hydroxymethylgroup, provided that at least one of X²¹ and X²² is a hydroxymethylgroup;

wherein R³¹ and R³² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar³¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR³¹ may combine to form a ring via R³¹; the two benzene rings linked viaR³² may combine to form a ring via R³²; letter symbols q and r are eachindependently 0 or 1; and X³¹ to X³⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX³¹ to X³⁴ is a hydroxymethyl group;

wherein R⁴¹ to R⁴³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁴¹ may combine to form a ring via R⁴¹; the twobenzene rings linked via R⁴² may combine to form a ring via R⁴²; the twobenzene rings linked via R may combine to form a ring via R⁴³; lettersymbols s, t and u are each independently 0 or 1; and X⁴¹ to X⁴⁶ eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁴¹ to X⁴⁶ is a hydroxymethyl group; and

wherein R⁵² represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Z⁵¹ and Z⁵² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z⁵¹ and the benzene ring having Z⁵² maycombine via Z⁵¹ or Z⁵² to form a ring; a letter symbol v is 0 or 1; aletter symbol w is an integer of 1 to 4; and X⁵¹ and X⁵² eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁵¹ and X⁵² is a hydroxymethyl group. 30.The electrophotographic photosensitive member according to claim 25,which has a protective layer on said photosensitive layer, and saidsurface layer of the electrophotographic photosensitive member is theprotective layer.
 31. An electrophotographic photosensitive membercomprising a support and provided thereon a photosensitive layer,wherein; said electrophotographic photosensitive member has a surfacelayer which contains a cured product of a resol resin obtained byallowing a phenolic compound having hydroxyphenyl groups andcharge-transportable structure, to react with formaldehyde in thepresence of a basic catalyst; said resol resin havingcharge-transportable structure.
 32. The electrophotographicphotosensitive member according to claim 31, wherein at least one ofsaid hydroxyphenyl groups is a p-hydroxyphenyl group.
 33. Theelectrophotographic photosensitive member according to claim 31, whereinsaid charge-transportable structure is triarylamine structure.
 34. Theelectrophotographic photosensitive member according to claim 31, whereinsaid phenolic compound having hydroxyphenyl groups andcharge-transportable structure has structure represented by any one ofthe following Formulas (6) to (10):

wherein R⁶¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched. R⁶² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar⁶¹ andAr⁶² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar⁶³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; and letter symbols m′ and n′ are eachindependently 0 or 1;

wherein R⁷¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar⁷¹ and Ar⁷² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R⁷¹; and a letter symbol p′ is 0 or 1;

wherein R⁸¹ and R⁸² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar⁸¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR⁸¹ may combine to form a ring via R⁸¹; the two benzene rings linked viaR⁸² may combine to form a ring via R⁸²; and letter symbols q′ and r′ areeach independently 0 or 1;

wherein R⁹¹ to R⁹³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁹¹ may combine to form a ring via R⁹¹; the twobenzene rings linked via R⁹² may combine to form a ring via R⁹²; the twobenzene rings linked via R⁹³ may combine to form a ring via R⁹³; lettersymbols s′, t′ and u′ are each independently 0 or 1; and

wherein R¹⁰² represents a divalent hydrocarbon group having 1 to 8carbon atoms and which may be branched; Z¹⁰¹ and Z¹⁰² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z¹⁰¹ and the benzene ring having Z¹⁰² maycombine via Z¹⁰¹ or Z¹⁰² to form a ring; a letter symbol v′ is 0 or 1;and a letter symbol w′ is an integer of 1 to
 4. 35. Theelectrophotographic photosensitive member according to claim 31, whereinsaid basic catalyst is an amine catalyst.
 36. The electrophotographicphotosensitive member according to claim 35, wherein said amine catalystis a tertiary alkylamine.
 37. The electrophotographic photosensitivemember according to claim 31, wherein said basic catalyst is a catalystcontaining an alkali metal or a catalyst containing an alkaline earthmetal.
 38. The electrophotographic photosensitive member according toclaim 31, which has a protective layer on said photosensitive layer, andsaid surface layer of the electrophotographic photosensitive member isthe protective layer.
 39. A process cartridge comprising anelectrophotographic photosensitive member and a means selected from thegroup consisting of a charging means, a developing means, a transfermeans and a cleaning means which are integrally supported, and beingdetachably mountable to the main body of an electrophotographicapparatus, wherein; said electrophotographic photosensitive member is anelectrophotographic photosensitive member comprising a support andprovided thereon a photosensitive layer; said electrophotographicphotosensitive member having a surface layer which contains a curedproduct of a phenolic compound having a plurality of substitutedhydroxyphenyl groups and charge-transportable structure; at least one ofsaid substituted hydroxyphenyl groups having at least one hydroxymethylgroup as a substituent.
 40. The process cartridge according to claim 39wherein at least one of said substituted hydroxyphenyl groups is asubstituted p-hydroxyphenyl group.
 41. The process cartridge accordingto claim 39 wherein at least one of said hydroxymethyl groups is linkedat the position which is the o-position in respect to any of thehydroxyl groups of the substituted hydroxyphenyl groups having ahydroxymethyl group as a substituent.
 42. The process cartridgeaccording to claim 39 wherein said charge-transportable structure istriarylamine structure.
 43. The process cartridge according to claim 39,wherein said phenolic compound has structure represented by any one ofthe following Formulas (1) to (5):

wherein R¹¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; R¹² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar¹¹ andAr¹² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar¹³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; letter symbols m and n are eachindependently 0 or 1; and X¹¹ to X¹⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX¹¹ to X¹⁴ is a hydroxymethyl group;

wherein R²¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar²¹ and Ar²² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R²¹; a letter symbol p is 0 or 1; and X²¹ andX²² each independently represent a hydrogen atom or a hydroxymethylgroup, provided that at least one of X²¹ and X²² is a hydroxymethylgroup;

wherein R³¹ and R³² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar³¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR³¹ may combine to form a ring via R³; the two benzene rings linked viaR³² may combine to form a ring via R³²; letter symbols q and r are eachindependently 0 or 1; and X³¹ to X³⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX³¹ to X³⁴ is a hydroxymethyl group;

wherein R⁴¹ to R⁴³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁴¹ may combine to form a ring via R⁴¹; the twobenzene rings linked via R⁴² may combine to form a ring via R⁴²; the twobenzene rings linked via R⁴³ may combine to form a ring via R⁴³; lettersymbols s, t and u are each independently 0 or 1; and X⁴¹ to X⁴⁶ eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁴ to X⁴⁶ is a hydroxymethyl group; and

wherein R⁵² represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Z⁵¹ and Z⁵² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z⁵¹ and the benzene ring having Z⁵² maycombine via Z⁵¹ or Z⁵² to form a ring; a letter symbol v is 0 or 1; aletter symbol w is an integer of 1 to 4; and X⁵¹ and X⁵² eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁵¹ and X⁵² is a hydroxymethyl group. 44.The process cartridge according to claim 39, wherein said surface layerof the electrophotographic photosensitive member is a protective layer.45. A process cartridge comprising an electrophotographic photosensitivemember and at least one means selected from the group consisting of acharging means, a developing means, a transfer means and a cleaningmeans which are integrally supported, and being detachably mountable tothe main body of an electrophotographic apparatus, wherein; saidelectrophotographic photosensitive member is an electrophotographicphotosensitive member comprising a support and provided thereon aphotosensitive layer; said electrophotographic photosensitive memberhaving a surface layer which contains a cured product of a resol resinobtained by allowing a phenolic compound having hydroxyphenyl groups andcharge-transportable structure, to react with formaldehyde in thepresence of a basic catalyst; said resol resin havingcharge-transportable structure.
 46. The process cartridge according toclaim 45, wherein at least one of said hydroxyphenyl groups is ap-hydroxyphenyl group.
 47. The process cartridge according to claim 45,wherein said charge-transportable structure is triarylamine structure.48. The process cartridge according to claim 45, wherein said phenoliccompound having hydroxyphenyl groups and charge-transportable structurehas structure represented by any one of the following Formulas (6) to(10):

wherein R⁶¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched. R⁶² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar⁶¹ andAr⁶² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar⁶³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; and letter symbols m′ and n′ are eachindependently 0 or 1;

wherein R⁷¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar⁷¹ and Ar⁷² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R⁷¹; and a letter symbol p′ is 0 or 1;

wherein R⁸¹ and R⁸² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar⁸¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR⁸¹ may combine to form a ring via R⁸¹; the two benzene rings linked viaR⁸² may combine to form a ring via R⁸²; and letter symbols q′ and r′ areeach independently 0 or 1;

wherein R⁹¹ to R⁹³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁹¹ may combine to form a ring via R⁹¹; the twobenzene rings linked via R⁹² may combine to form a ring via R⁹²; the twobenzene rings linked via R⁹³ may combine to form a ring via R⁹³; lettersymbols s′, t′ and u′ are each independently 0 or 1; and

wherein R¹⁰² represents a divalent hydrocarbon group having 1 to 8carbon atoms and which may be branched; Z¹⁰¹ and Z¹⁰² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z¹⁰¹ and the benzene ring having Z¹⁰² maycombine via Z¹⁰¹ or Z¹⁰² to form a ring; a letter symbol v′ is 0 or 1;and a letter symbol w′ is an integer of 1 to
 4. 49. The processcartridge according to claim 45, wherein said basic catalyst is an aminecatalyst.
 50. The process cartridge according to claim 49, wherein saidamine catalyst is a tertiary alkylamine.
 51. The process cartridgeaccording to claim 45, wherein said basic catalyst is a catalystcontaining an alkali metal or a catalyst containing an alkaline earthmetal.
 52. The process cartridge according to claim 45, wherein saidelectrophotographic photosensitive member has a protective layer on saidphotosensitive layer, and said surface layer of the electrophotographicphotosensitive member is the protective layer.
 53. Anelectrophotographic apparatus comprising an electrophotographicphotosensitive member, a charging means, an exposure means, a developingmeans and a transfer means, wherein; said electrophotographicphotosensitive member is an electrophotographic photosensitive membercomprising a support and provided thereon a photosensitive layer; saidelectrophotographic photosensitive member having a surface layer whichcontains a cured product of a phenolic compound having a plurality ofsubstituted hydroxyphenyl groups and charge-transportable structure; atleast one of said substituted hydroxyphenyl groups having at least onehydroxymethyl group as a substituent.
 54. The electrophotographicapparatus according to claim 53, wherein at least one of saidsubstituted hydroxyphenyl groups is a substituted p-hydroxyphenyl group.55. The electrophotographic apparatus according to claim 53, wherein atleast one of said hydroxymethyl groups is linked at the position whichis the o-position in respect to any of the hydroxyl groups of thesubstituted hydroxyphenyl groups having a hydroxymethyl group as asubstituent.
 56. The electrophotographic apparatus according to claim53, wherein said charge-transportable structure is triarylaminestructure.
 57. The electrophotographic apparatus according to claim 53,wherein said phenolic compound has structure represented by any one ofthe following Formulas (1) to (5):

wherein R¹¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; R¹² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar¹¹ andAr¹² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar¹³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; letter symbols m and n are eachindependently 0 or 1; and X¹¹ to X¹⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX¹¹ to X¹⁴ is a hydroxymethyl group;

wherein R²¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar²¹ and Ar²² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R²¹; a letter symbol p is 0 or 1; and X²¹ andX²² each independently represent a hydrogen atom or a hydroxymethylgroup, provided that at least one of X²¹ and X²² is a hydroxymethylgroup;

wherein R³¹ and R³² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar³:represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR³¹ may combine to form a ring via R³¹; the two benzene rings linked viaR³² may combine to form a ring via R³²; letter symbols q and r are eachindependently 0 or 1; and X³¹ to X³⁴ each independently represent ahydrogen atom or a hydroxymethyl group, provided that at least one ofX³¹ to X³⁴ is a hydroxymethyl group;

wherein R⁴¹ to R⁴³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁴¹ may combine to form a ring via R⁴¹; the twobenzene rings linked via R⁴² may combine to form a ring via R⁴²; the twobenzene rings linked via R⁴³ may combine to form a ring via R⁴³; lettersymbols s, t and u are each independently 0 or 1; and X⁴¹ to X⁴⁶ eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁴¹ to X⁴⁶ is a hydroxymethyl group; and

wherein R⁵² represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Z⁵¹ and Z⁵² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z⁵¹ and the benzene ring having Z⁵² maycombine via Z⁵¹ or Z⁵² to form a ring; a letter symbol v is 0 or 1; aletter symbol w is an integer of 1 to 4; and X⁵¹ and X⁵² eachindependently represent a hydrogen atom or a hydroxymethyl group,provided that at least one of X⁵¹ and X⁵² is a hydroxymethyl group. 58.The electrophotographic apparatus according to claim 53, wherein saidelectrophotographic photosensitive member has a protective layer on saidphotosensitive layer, and said surface layer of the electrophotographicphotosensitive member is the protective layer.
 59. Anelectrophotographic apparatus comprising an electrophotographicphotosensitive member, a charging means, an exposure means, a developingmeans and a transfer means, wherein; said electrophotographicphotosensitive member is an electrophotographic photosensitive membercomprising a support and provided thereon a photosensitive layer; saidelectrophotographic photosensitive member having a surface layer whichcontains a cured product of a resol resin obtained by allowing aphenolic compound having hydroxyphenyl groups and charge-transportablestructure, to react with formaldehyde in the presence of a basiccatalyst; said resol resin having charge-transportable structure. 60.The electrophotographic apparatus according to claim 59, wherein atleast one of said hydroxyphenyl groups is a p-hydroxyphenyl group. 61.The electrophotographic apparatus according to claim 59, wherein saidcharge-transportable structure is triarylamine structure.
 62. Theelectrophotographic apparatus according to claim 59, wherein saidphenolic compound having hydroxyphenyl groups and charge-transportablestructure has structure represented by any one of the following Formulas(6) to (10):

wherein R⁶¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched. R⁶² represents a hydrogen atom, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedaralkyl group or a substituted or unsubstituted phenyl group; Ar⁶¹ andAr⁶² each independently represent a substituted or unsubstituted alkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted monovalent aromatic hydrocarbon ring group or asubstituted or unsubstituted monovalent aromatic heterocyclic group;Ar⁶³ represents a substituted or unsubstituted divalent aromatichydrocarbon ring group or a substituted or unsubstituted divalentaromatic heterocyclic group; and letter symbols m′ and n′ are eachindependently 0 or 1;

wherein R⁷¹ represents a divalent hydrocarbon group having 1 to 8 carbonatoms and which may be branched; Ar⁷¹ and Ar⁷² each independentlyrepresent a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings maycombine to form a ring via R⁷¹; and a letter symbol p′ is 0 or 1;

wherein R⁸¹ and R⁸² each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; Ar⁸¹represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted monovalentaromatic hydrocarbon ring group or a substituted or unsubstitutedmonovalent aromatic heterocyclic group; the two benzene rings linked viaR⁸¹ may combine to form a ring via R⁸¹; the two benzene rings linked viaR⁸² may combine to form a ring via R⁸²; and letter symbols q′ and r′ areeach independently 0 or 1;

wherein R⁹¹ to R⁹³ each independently represent a divalent hydrocarbongroup having 1 to 8 carbon atoms and which may be branched; the twobenzene rings linked via R⁹¹ may combine to form a ring via R⁹¹; the twobenzene rings linked via R⁹² may combine to form a ring via R⁹²; the twobenzene rings linked via R⁹³ may combine to form a ring via R⁹³; lettersymbols s′, t′ and u′ are each independently 0 or 1; and

wherein R¹⁰² represents a divalent hydrocarbon group having 1 to 8carbon atoms and which may be branched; Z¹⁰¹ and Z¹⁰² each independentlyrepresent a hydrogen atom, a halogen atom, a substituted orunsubstituted alkyl group, a substituted or unsubstituted aralkyl group,a substituted or unsubstituted monovalent aromatic hydrocarbon ringgroup or a substituted or unsubstituted monovalent aromatic heterocyclicgroup; the benzene ring having Z¹⁰¹ and the benzene ring having Z¹⁰² maycombine via Z¹⁰¹ or Z¹⁰² to form a ring; a letter symbol v′ is 0 or 1;and a letter symbol w′ is an integer of 1 to
 4. 63. Theelectrophotographic apparatus according to claim 59, wherein said basiccatalyst is an amine catalyst.
 64. The electrophotographic apparatusaccording to claim 63, wherein said amine catalyst is a tertiaryalkylamine.
 65. The electrophotographic apparatus according to claim 59,wherein said basic catalyst is a catalyst containing an alkali metal ora catalyst containing an alkaline earth metal.
 66. Theelectrophotographic apparatus according to claim 59, wherein saidelectrophotographic photosensitive member has a protective layer on saidphotosensitive layer, and said surface layer of the electrophotographicphotosensitive member is the protective layer.